diff --git a/circuits/README.md b/circuits/README.md
index fc66f6b0c0dc..4d879148b57e 100644
--- a/circuits/README.md
+++ b/circuits/README.md
@@ -70,6 +70,10 @@ You can choose which tests will run via a gtest filter. This one below runs only
 ./scripts/run_tests_local wasm aztec3_circuits_abis_tests -*.circuit*
 ```
 
+> _Note:_ To log wasm output from within TS that uses them, you can use before running your `yarn test`
+```
+export DEBUG='wasm'
+```
 ---
 
 Here's a list of the tests currently available (conveniently combined with the command to build, then execute them on `x86_64`, for easy copy-pasta):
diff --git a/circuits/cpp/src/aztec3/circuits/abis/combined_accumulated_data.hpp b/circuits/cpp/src/aztec3/circuits/abis/combined_accumulated_data.hpp
index 083dd054fb92..2751f63db339 100644
--- a/circuits/cpp/src/aztec3/circuits/abis/combined_accumulated_data.hpp
+++ b/circuits/cpp/src/aztec3/circuits/abis/combined_accumulated_data.hpp
@@ -36,7 +36,8 @@ template <typename NCT> struct CombinedAccumulatedData {
         zero_array<fr, KERNEL_PRIVATE_CALL_STACK_LENGTH>();
     std::array<fr, KERNEL_PUBLIC_CALL_STACK_LENGTH> public_call_stack =
         zero_array<fr, KERNEL_PUBLIC_CALL_STACK_LENGTH>();
-    std::array<fr, KERNEL_L1_MSG_STACK_LENGTH> l1_msg_stack = zero_array<fr, KERNEL_L1_MSG_STACK_LENGTH>();
+    std::array<fr, KERNEL_NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs =
+        zero_array<fr, KERNEL_NEW_L2_TO_L1_MSGS_LENGTH>();
 
     std::array<NewContractData<NCT>, KERNEL_NEW_CONTRACTS_LENGTH> new_contracts{};
 
@@ -50,7 +51,7 @@ template <typename NCT> struct CombinedAccumulatedData {
         return aggregation_object == other.aggregation_object && private_call_count == other.private_call_count &&
                public_call_count == other.public_call_count && new_commitments == other.new_commitments &&
                new_nullifiers == other.new_nullifiers && private_call_stack == other.private_call_stack &&
-               public_call_stack == other.public_call_stack && l1_msg_stack == other.l1_msg_stack &&
+               public_call_stack == other.public_call_stack && new_l2_to_l1_msgs == other.new_l2_to_l1_msgs &&
                new_contracts == other.new_contracts && optionally_revealed_data == other.optionally_revealed_data &&
                state_transitions == other.state_transitions && state_reads == other.state_reads;
     };
@@ -82,7 +83,7 @@ template <typename NCT> struct CombinedAccumulatedData {
 
             to_ct(private_call_stack),
             to_ct(public_call_stack),
-            to_ct(l1_msg_stack),
+            to_ct(new_l2_to_l1_msgs),
 
             map(new_contracts, to_circuit_type),
             map(optionally_revealed_data, to_circuit_type),
@@ -116,7 +117,7 @@ template <typename NCT> struct CombinedAccumulatedData {
 
             to_nt(private_call_stack),
             to_nt(public_call_stack),
-            to_nt(l1_msg_stack),
+            to_nt(new_l2_to_l1_msgs),
 
             map(new_contracts, to_native_type),
             map(optionally_revealed_data, to_native_type),
@@ -140,7 +141,7 @@ template <typename NCT> struct CombinedAccumulatedData {
 
         set_array_public(private_call_stack);
         set_array_public(public_call_stack);
-        set_array_public(l1_msg_stack);
+        set_array_public(new_l2_to_l1_msgs);
 
         set_array_public(new_contracts);
         set_array_public(optionally_revealed_data);
@@ -200,7 +201,7 @@ template <typename NCT> void read(uint8_t const*& it, CombinedAccumulatedData<NC
     read(it, accum_data.new_nullifiers);
     read(it, accum_data.private_call_stack);
     read(it, accum_data.public_call_stack);
-    read(it, accum_data.l1_msg_stack);
+    read(it, accum_data.new_l2_to_l1_msgs);
     read(it, accum_data.new_contracts);
     read(it, accum_data.optionally_revealed_data);
     read(it, accum_data.state_transitions);
@@ -218,7 +219,7 @@ template <typename NCT> void write(std::vector<uint8_t>& buf, CombinedAccumulate
     write(buf, accum_data.new_nullifiers);
     write(buf, accum_data.private_call_stack);
     write(buf, accum_data.public_call_stack);
-    write(buf, accum_data.l1_msg_stack);
+    write(buf, accum_data.new_l2_to_l1_msgs);
     write(buf, accum_data.new_contracts);
     write(buf, accum_data.optionally_revealed_data);
     write(buf, accum_data.state_transitions);
@@ -239,8 +240,8 @@ template <typename NCT> std::ostream& operator<<(std::ostream& os, CombinedAccum
               << accum_data.private_call_stack << "\n"
               << "public_call_stack:\n"
               << accum_data.public_call_stack << "\n"
-              << "l1_msg_stack:\n"
-              << accum_data.l1_msg_stack << "\n"
+              << "new_l2_to_l1_msgs:\n"
+              << accum_data.new_l2_to_l1_msgs << "\n"
               << "new_contracts:\n"
               << accum_data.new_contracts << "\n"
               << "optionally_revealed_data:\n"
diff --git a/circuits/cpp/src/aztec3/circuits/abis/private_circuit_public_inputs.hpp b/circuits/cpp/src/aztec3/circuits/abis/private_circuit_public_inputs.hpp
index 1c3e287bc4ef..e6b0d89d5be8 100644
--- a/circuits/cpp/src/aztec3/circuits/abis/private_circuit_public_inputs.hpp
+++ b/circuits/cpp/src/aztec3/circuits/abis/private_circuit_public_inputs.hpp
@@ -36,7 +36,7 @@ template <typename NCT> class PrivateCircuitPublicInputs {
 
     std::array<fr, PRIVATE_CALL_STACK_LENGTH> private_call_stack = zero_array<fr, PRIVATE_CALL_STACK_LENGTH>();
     std::array<fr, PUBLIC_CALL_STACK_LENGTH> public_call_stack = zero_array<fr, PUBLIC_CALL_STACK_LENGTH>();
-    std::array<fr, L1_MSG_STACK_LENGTH> l1_msg_stack = zero_array<fr, L1_MSG_STACK_LENGTH>();
+    std::array<fr, NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs = zero_array<fr, NEW_L2_TO_L1_MSGS_LENGTH>();
 
     fr historic_private_data_tree_root = 0;
     fr historic_nullifier_tree_root = 0;
@@ -49,7 +49,7 @@ template <typename NCT> class PrivateCircuitPublicInputs {
         return call_context == other.call_context && args == other.args && return_values == other.return_values &&
                emitted_events == other.emitted_events && new_commitments == other.new_commitments &&
                new_nullifiers == other.new_nullifiers && private_call_stack == other.private_call_stack &&
-               public_call_stack == other.public_call_stack && l1_msg_stack == other.l1_msg_stack &&
+               public_call_stack == other.public_call_stack && new_l2_to_l1_msgs == other.new_l2_to_l1_msgs &&
                historic_private_data_tree_root == other.historic_private_data_tree_root &&
                historic_nullifier_tree_root == other.historic_nullifier_tree_root &&
                historic_contract_tree_root == other.historic_contract_tree_root &&
@@ -78,7 +78,7 @@ template <typename NCT> class PrivateCircuitPublicInputs {
 
             to_ct(private_call_stack),
             to_ct(public_call_stack),
-            to_ct(l1_msg_stack),
+            to_ct(new_l2_to_l1_msgs),
 
             to_ct(historic_private_data_tree_root),
             to_ct(historic_nullifier_tree_root),
@@ -109,7 +109,7 @@ template <typename NCT> class PrivateCircuitPublicInputs {
 
             to_nt(private_call_stack),
             to_nt(public_call_stack),
-            to_nt(l1_msg_stack),
+            to_nt(new_l2_to_l1_msgs),
 
             to_nt(historic_private_data_tree_root),
             to_nt(historic_nullifier_tree_root),
@@ -139,7 +139,7 @@ template <typename NCT> class PrivateCircuitPublicInputs {
 
         spread_arr_into_vec(private_call_stack, inputs);
         spread_arr_into_vec(public_call_stack, inputs);
-        spread_arr_into_vec(l1_msg_stack, inputs);
+        spread_arr_into_vec(new_l2_to_l1_msgs, inputs);
 
         inputs.push_back(historic_private_data_tree_root);
         inputs.push_back(historic_nullifier_tree_root);
@@ -170,7 +170,7 @@ template <typename NCT> void read(uint8_t const*& it, PrivateCircuitPublicInputs
     read(it, pis.new_nullifiers);
     read(it, pis.private_call_stack);
     read(it, pis.public_call_stack);
-    read(it, pis.l1_msg_stack);
+    read(it, pis.new_l2_to_l1_msgs);
     read(it, pis.historic_private_data_tree_root);
     read(it, pis.historic_nullifier_tree_root);
     read(it, pis.historic_contract_tree_root);
@@ -192,7 +192,7 @@ void write(std::vector<uint8_t>& buf, PrivateCircuitPublicInputs<NCT> const& pri
     write(buf, pis.new_nullifiers);
     write(buf, pis.private_call_stack);
     write(buf, pis.public_call_stack);
-    write(buf, pis.l1_msg_stack);
+    write(buf, pis.new_l2_to_l1_msgs);
     write(buf, pis.historic_private_data_tree_root);
     write(buf, pis.historic_nullifier_tree_root);
     write(buf, pis.historic_contract_tree_root);
@@ -213,7 +213,7 @@ std::ostream& operator<<(std::ostream& os, PrivateCircuitPublicInputs<NCT> const
               << "new_nullifiers: " << pis.new_nullifiers << "\n"
               << "private_call_stack: " << pis.private_call_stack << "\n"
               << "public_call_stack: " << pis.public_call_stack << "\n"
-              << "l1_msg_stack: " << pis.l1_msg_stack << "\n"
+              << "new_l2_to_l1_msgs: " << pis.new_l2_to_l1_msgs << "\n"
               << "historic_private_data_tree_root: " << pis.historic_private_data_tree_root << "\n"
               << "historic_nullifier_tree_root: " << pis.historic_nullifier_tree_root << "\n"
               << "contract_deployment_data: " << pis.contract_deployment_data << "\n"
@@ -241,7 +241,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
     std::array<opt_fr, PRIVATE_CALL_STACK_LENGTH> private_call_stack;
     std::array<opt_fr, PUBLIC_CALL_STACK_LENGTH> public_call_stack;
-    std::array<opt_fr, L1_MSG_STACK_LENGTH> l1_msg_stack;
+    std::array<opt_fr, NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs;
 
     opt_fr historic_private_data_tree_root;
     opt_fr historic_nullifier_tree_root;
@@ -263,7 +263,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
                                             std::array<opt_fr, PRIVATE_CALL_STACK_LENGTH> const& private_call_stack,
                                             std::array<opt_fr, PUBLIC_CALL_STACK_LENGTH> const& public_call_stack,
-                                            std::array<opt_fr, L1_MSG_STACK_LENGTH> const& l1_msg_stack,
+                                            std::array<opt_fr, NEW_L2_TO_L1_MSGS_LENGTH> const& new_l2_to_l1_msgs,
 
                                             opt_fr const& historic_private_data_tree_root,
                                             opt_fr const& historic_nullifier_tree_root,
@@ -278,7 +278,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
         , new_nullifiers(new_nullifiers)
         , private_call_stack(private_call_stack)
         , public_call_stack(public_call_stack)
-        , l1_msg_stack(l1_msg_stack)
+        , new_l2_to_l1_msgs(new_l2_to_l1_msgs)
         , historic_private_data_tree_root(historic_private_data_tree_root)
         , historic_nullifier_tree_root(historic_nullifier_tree_root)
         , historic_contract_tree_root(historic_contract_tree_root)
@@ -303,7 +303,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
         new_inputs.private_call_stack.fill(std::nullopt);
         new_inputs.public_call_stack.fill(std::nullopt);
-        new_inputs.l1_msg_stack.fill(std::nullopt);
+        new_inputs.new_l2_to_l1_msgs.fill(std::nullopt);
 
         new_inputs.historic_private_data_tree_root = std::nullopt;
         new_inputs.historic_nullifier_tree_root = std::nullopt;
@@ -350,7 +350,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
         make_unused_array_elements_zero(composer, private_call_stack);
         make_unused_array_elements_zero(composer, public_call_stack);
-        make_unused_array_elements_zero(composer, l1_msg_stack);
+        make_unused_array_elements_zero(composer, new_l2_to_l1_msgs);
 
         make_unused_element_zero(composer, historic_private_data_tree_root);
         make_unused_element_zero(composer, historic_nullifier_tree_root);
@@ -381,7 +381,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
         set_array_public(private_call_stack);
         set_array_public(public_call_stack);
-        set_array_public(l1_msg_stack);
+        set_array_public(new_l2_to_l1_msgs);
 
         (*historic_private_data_tree_root).set_public();
         (*historic_nullifier_tree_root).set_public();
@@ -414,7 +414,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
             to_ct(private_call_stack),
             to_ct(public_call_stack),
-            to_ct(l1_msg_stack),
+            to_ct(new_l2_to_l1_msgs),
 
             to_ct(historic_private_data_tree_root),
             to_ct(historic_nullifier_tree_root),
@@ -448,7 +448,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
             to_nt(private_call_stack),
             to_nt(public_call_stack),
-            to_nt(l1_msg_stack),
+            to_nt(new_l2_to_l1_msgs),
 
             to_nt(historic_private_data_tree_root),
             to_nt(historic_nullifier_tree_root),
@@ -483,7 +483,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
         spread_arr_opt_into_vec(private_call_stack, inputs);
         spread_arr_opt_into_vec(public_call_stack, inputs);
-        spread_arr_opt_into_vec(l1_msg_stack, inputs);
+        spread_arr_opt_into_vec(new_l2_to_l1_msgs, inputs);
 
         inputs.push_back(*historic_private_data_tree_root);
         inputs.push_back(*historic_nullifier_tree_root);
@@ -512,7 +512,7 @@ template <typename NCT> class OptionalPrivateCircuitPublicInputs {
 
             .private_call_stack = map(private_call_stack, get_value),
             .public_call_stack = map(public_call_stack, get_value),
-            .l1_msg_stack = map(l1_msg_stack, get_value),
+            .new_l2_to_l1_msgs = map(new_l2_to_l1_msgs, get_value),
 
             .historic_private_data_tree_root = historic_private_data_tree_root.value(),
             .historic_nullifier_tree_root = historic_nullifier_tree_root.value(),
@@ -604,7 +604,7 @@ void read(uint8_t const*& it, OptionalPrivateCircuitPublicInputs<NCT>& private_c
     read(it, pis.new_nullifiers);
     read(it, pis.private_call_stack);
     read(it, pis.public_call_stack);
-    read(it, pis.l1_msg_stack);
+    read(it, pis.new_l2_to_l1_msgs);
     read(it, pis.historic_private_data_tree_root);
     read(it, pis.historic_nullifier_tree_root);
     read(it, pis.historic_contract_tree_root);
@@ -626,7 +626,7 @@ void write(std::vector<uint8_t>& buf, OptionalPrivateCircuitPublicInputs<NCT> co
     write(buf, pis.new_nullifiers);
     write(buf, pis.private_call_stack);
     write(buf, pis.public_call_stack);
-    write(buf, pis.l1_msg_stack);
+    write(buf, pis.new_l2_to_l1_msgs);
     write(buf, pis.historic_private_data_tree_root);
     write(buf, pis.historic_nullifier_tree_root);
     write(buf, pis.historic_contract_tree_root);
@@ -646,7 +646,7 @@ std::ostream& operator<<(std::ostream& os, OptionalPrivateCircuitPublicInputs<NC
               << "new_nullifiers: " << pis.new_nullifiers << "\n"
               << "private_call_stack: " << pis.private_call_stack << "\n"
               << "public_call_stack: " << pis.public_call_stack << "\n"
-              << "l1_msg_stack: " << pis.l1_msg_stack << "\n"
+              << "new_l2_to_l1_msgs: " << pis.new_l2_to_l1_msgs << "\n"
               << "historic_private_data_tree_root: " << pis.historic_private_data_tree_root << "\n"
               << "historic_nullifier_tree_root: " << pis.historic_nullifier_tree_root << "\n"
               << "historic_nullifier_tree_root: " << pis.historic_nullifier_tree_root << "\n"
diff --git a/circuits/cpp/src/aztec3/circuits/abis/private_kernel/call_context_reconciliation_data.hpp b/circuits/cpp/src/aztec3/circuits/abis/private_kernel/call_context_reconciliation_data.hpp
index 3635b44e6116..bc1b8d39d42f 100644
--- a/circuits/cpp/src/aztec3/circuits/abis/private_kernel/call_context_reconciliation_data.hpp
+++ b/circuits/cpp/src/aztec3/circuits/abis/private_kernel/call_context_reconciliation_data.hpp
@@ -30,8 +30,8 @@
 
 //     // std::array<fr, CONTRACT_DEPLOYMENT_CALL_STACK_LENGTH> contract_deployment_call_stack;
 
-//     std::array<CallContext<NCT>, L1_MSG_STACK_LENGTH> l1_call_contexts;
-//     std::array<fr, L1_MSG_STACK_LENGTH> l1_counterparts; // TODO: this is probably wrong.
+//     std::array<CallContext<NCT>, NEW_L2_TO_L1_MSGS_LENGTH> l1_call_contexts;
+//     std::array<fr, NEW_L2_TO_L1_MSGS_LENGTH> l1_counterparts; // TODO: this is probably wrong.
 
 //     template <typename Composer>
 //     CallContextReconciliationData<CircuitTypes<Composer>> to_circuit_type(Composer& composer) const
diff --git a/circuits/cpp/src/aztec3/circuits/abis/public_circuit_public_inputs.hpp b/circuits/cpp/src/aztec3/circuits/abis/public_circuit_public_inputs.hpp
index 9e90e80db6d5..a5169aae2e3a 100644
--- a/circuits/cpp/src/aztec3/circuits/abis/public_circuit_public_inputs.hpp
+++ b/circuits/cpp/src/aztec3/circuits/abis/public_circuit_public_inputs.hpp
@@ -33,7 +33,7 @@ template <typename NCT> struct PublicCircuitPublicInputs {
     std::array<StateRead<NCT>, STATE_READS_LENGTH> state_reads{};
 
     std::array<fr, PUBLIC_CALL_STACK_LENGTH> public_call_stack = zero_array<fr, PUBLIC_CALL_STACK_LENGTH>();
-    std::array<fr, L1_MSG_STACK_LENGTH> l1_msg_stack = zero_array<fr, L1_MSG_STACK_LENGTH>();
+    std::array<fr, NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs = zero_array<fr, NEW_L2_TO_L1_MSGS_LENGTH>();
 
     fr historic_public_data_tree_root = 0;
 
@@ -44,7 +44,7 @@ template <typename NCT> struct PublicCircuitPublicInputs {
         return call_context == other.call_context && args == other.args && return_values == other.return_values &&
                emitted_events == other.emitted_events && state_transitions == other.state_transitions &&
                state_reads == other.state_reads && public_call_stack == other.public_call_stack &&
-               l1_msg_stack == other.l1_msg_stack &&
+               new_l2_to_l1_msgs == other.new_l2_to_l1_msgs &&
                historic_public_data_tree_root == other.historic_public_data_tree_root &&
                prover_address == other.prover_address;
     };
@@ -70,7 +70,7 @@ template <typename NCT> struct PublicCircuitPublicInputs {
             .state_reads = map(state_reads, to_circuit_type),
 
             .public_call_stack = to_ct(public_call_stack),
-            .l1_msg_stack = to_ct(l1_msg_stack),
+            .new_l2_to_l1_msgs = to_ct(new_l2_to_l1_msgs),
 
             .historic_public_data_tree_root = to_ct(historic_public_data_tree_root),
 
@@ -99,7 +99,7 @@ template <typename NCT> struct PublicCircuitPublicInputs {
         spread_arr_into_vec(map(state_reads, to_hashes), inputs);
 
         spread_arr_into_vec(public_call_stack, inputs);
-        spread_arr_into_vec(l1_msg_stack, inputs);
+        spread_arr_into_vec(new_l2_to_l1_msgs, inputs);
 
         inputs.push_back(historic_public_data_tree_root);
 
@@ -127,7 +127,7 @@ template <typename NCT> void read(uint8_t const*& it, PublicCircuitPublicInputs<
     read(it, pis.state_reads);
 
     read(it, pis.public_call_stack);
-    read(it, pis.l1_msg_stack);
+    read(it, pis.new_l2_to_l1_msgs);
 
     read(it, pis.historic_public_data_tree_root);
 
@@ -150,7 +150,7 @@ void write(std::vector<uint8_t>& buf, PublicCircuitPublicInputs<NCT> const& publ
     write(buf, pis.state_reads);
 
     write(buf, pis.public_call_stack);
-    write(buf, pis.l1_msg_stack);
+    write(buf, pis.new_l2_to_l1_msgs);
 
     write(buf, pis.historic_public_data_tree_root);
 
@@ -171,7 +171,7 @@ std::ostream& operator<<(std::ostream& os, PublicCircuitPublicInputs<NCT> const&
               << "state_reads: " << pis.state_reads << "\n"
 
               << "public_call_stack: " << pis.public_call_stack << "\n"
-              << "l1_msg_stack: " << pis.l1_msg_stack << "\n"
+              << "new_l2_to_l1_msgs: " << pis.new_l2_to_l1_msgs << "\n"
 
               << "historic_public_data_tree_root: " << pis.historic_public_data_tree_root << "\n"
 
diff --git a/circuits/cpp/src/aztec3/circuits/abis/rollup/root/root_rollup_inputs.hpp b/circuits/cpp/src/aztec3/circuits/abis/rollup/root/root_rollup_inputs.hpp
index f93c3fcbaaaa..0f2ba96f71fc 100644
--- a/circuits/cpp/src/aztec3/circuits/abis/rollup/root/root_rollup_inputs.hpp
+++ b/circuits/cpp/src/aztec3/circuits/abis/rollup/root/root_rollup_inputs.hpp
@@ -50,9 +50,10 @@ template <typename NCT> void write(std::vector<uint8_t>& buf, RootRollupInputs<N
 template <typename NCT> std::ostream& operator<<(std::ostream& os, RootRollupInputs<NCT> const& obj)
 {
     return os << "previous_rollup_data: " << obj.previous_rollup_data << "\n"
-              << "new_historic_private_data_tree_roots: " << obj.new_historic_private_data_tree_root_sibling_path
-              << "\n"
-              << "new_historic_contract_tree_roots: " << obj.new_historic_contract_tree_root_sibling_path << "\n";
+              << "new_historic_private_data_tree_root_sibling_path: "
+              << obj.new_historic_private_data_tree_root_sibling_path << "\n"
+              << "new_historic_contract_tree_root_sibling_path: " << obj.new_historic_contract_tree_root_sibling_path
+              << "\n";
 }
 
 } // namespace aztec3::circuits::abis
\ No newline at end of file
diff --git a/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit.cpp b/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit.cpp
index 52a54e154bbb..b9f276730760 100644
--- a/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit.cpp
+++ b/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit.cpp
@@ -68,7 +68,7 @@ void initialise_end_values(PrivateInputs<NT> const& private_inputs, KernelCircui
 
     end.private_call_stack = start.private_call_stack;
     end.public_call_stack = start.public_call_stack;
-    end.l1_msg_stack = start.l1_msg_stack;
+    end.new_l2_to_l1_msgs = start.new_l2_to_l1_msgs;
 
     end.optionally_revealed_data = start.optionally_revealed_data;
 }
@@ -239,14 +239,14 @@ void update_end_values(DummyComposer& composer,
     // const auto& portal_contract_address = private_inputs.private_call.portal_contract_address;
 
     // {
-    //     const auto& l1_msg_stack = private_call_public_inputs.l1_msg_stack;
-    //     std::array<CT::fr, L1_MSG_STACK_LENGTH> l1_call_stack;
+    //     const auto& new_l2_to_l1_msgs = private_call_public_inputs.new_l2_to_l1_msgs;
+    //     std::array<CT::fr, NEW_L2_TO_L1_MSGS_LENGTH> l1_call_stack;
 
-    //     for (size_t i = 0; i < l1_msg_stack.size(); ++i) {
+    //     for (size_t i = 0; i < new_l2_to_l1_msgs.size(); ++i) {
     //         l1_call_stack[i] = CT::fr::conditional_assign(
-    //             l1_msg_stack[i] == 0,
+    //             new_l2_to_l1_msgs[i] == 0,
     //             0,
-    //             CT::compress({ portal_contract_address, l1_msg_stack[i] }, GeneratorIndex::L1_MSG_STACK_ITEM));
+    //             CT::compress({ portal_contract_address, new_l2_to_l1_msgs[i] }, GeneratorIndex::L1_MSG_STACK_ITEM));
     //     }
     // }
 }
@@ -299,7 +299,7 @@ void validate_inputs(DummyComposer& composer, PrivateInputs<NT> const& private_i
 
     NT::fr start_private_call_stack_length = array_length(start.private_call_stack);
     NT::fr start_public_call_stack_length = array_length(start.public_call_stack);
-    NT::fr start_l1_msg_stack_length = array_length(start.l1_msg_stack);
+    NT::fr start_new_l2_to_l1_msgs = array_length(start.new_l2_to_l1_msgs);
 
     // Base Case
     if (is_base_case) {
@@ -313,7 +313,7 @@ void validate_inputs(DummyComposer& composer, PrivateInputs<NT> const& private_i
         composer.do_assert(start_public_call_stack_length == 0,
                            "Public call stack must be empty",
                            CircuitErrorCode::PRIVATE_KERNEL__UNSUPPORTED_OP);
-        composer.do_assert(start_l1_msg_stack_length == 0,
+        composer.do_assert(start_new_l2_to_l1_msgs == 0,
                            "L1 msg stack must be empty",
                            CircuitErrorCode::PRIVATE_KERNEL__UNSUPPORTED_OP);
 
diff --git a/circuits/cpp/src/aztec3/circuits/kernel/private/private_kernel_circuit.cpp b/circuits/cpp/src/aztec3/circuits/kernel/private/private_kernel_circuit.cpp
index a7148faad668..3dc7259d7979 100644
--- a/circuits/cpp/src/aztec3/circuits/kernel/private/private_kernel_circuit.cpp
+++ b/circuits/cpp/src/aztec3/circuits/kernel/private/private_kernel_circuit.cpp
@@ -77,7 +77,7 @@ void initialise_end_values(PrivateInputs<CT> const& private_inputs, KernelCircui
 
     end.private_call_stack = start.private_call_stack;
     end.public_call_stack = start.public_call_stack;
-    end.l1_msg_stack = start.l1_msg_stack;
+    end.new_l2_to_l1_msgs = start.new_l2_to_l1_msgs;
 
     // TODO
     end.new_contracts = start.new_contracts;
@@ -187,14 +187,14 @@ void update_end_values(PrivateInputs<CT> const& private_inputs, KernelCircuitPub
     }
 
     // {
-    //     const auto& l1_msg_stack = private_call_public_inputs.l1_msg_stack;
-    //     std::array<CT::fr, L1_MSG_STACK_LENGTH> l1_call_stack;
+    //     const auto& new_l2_to_l1_msgs = private_call_public_inputs.new_l2_to_l1_msgs;
+    //     std::array<CT::fr, NEW_L2_TO_L1_MSGS_LENGTH> l1_call_stack;
 
-    //     for (size_t i = 0; i < l1_msg_stack.size(); ++i) {
+    //     for (size_t i = 0; i < new_l2_to_l1_msgs.size(); ++i) {
     //         l1_call_stack[i] = CT::fr::conditional_assign(
-    //             l1_msg_stack[i] == 0,
+    //             new_l2_to_l1_msgs[i] == 0,
     //             0,
-    //             CT::compress({ portal_contract_address, l1_msg_stack[i] }, GeneratorIndex::L1_MSG_STACK_ITEM));
+    //             CT::compress({ portal_contract_address, new_l2_to_l1_msgs[i] }, GeneratorIndex::L1_MSG_STACK_ITEM));
     //     }
     // }
 }
@@ -260,7 +260,7 @@ void validate_inputs(PrivateInputs<CT> const& private_inputs)
     // but we want to know "length" in terms of how many nonzero entries have been inserted
     CT::fr start_private_call_stack_length = array_length<Composer>(start.private_call_stack);
     CT::fr start_public_call_stack_length = array_length<Composer>(start.public_call_stack);
-    CT::fr start_l1_msg_stack_length = array_length<Composer>(start.l1_msg_stack);
+    CT::fr start_new_l2_to_l1_msgs = array_length<Composer>(start.new_l2_to_l1_msgs);
 
     // Recall: we can't do traditional `if` statements in a circuit; all code paths are always executed. The below is
     // some syntactic sugar, which seeks readability similar to an `if` statement.
@@ -271,7 +271,7 @@ void validate_inputs(PrivateInputs<CT> const& private_inputs)
         // rebate can be paid.
         { start_private_call_stack_length == 1, "Private call stack must be length 1" },
         { start_public_call_stack_length == 0, "Public call stack must be empty" },
-        { start_l1_msg_stack_length == 0, "L1 msg stack must be empty" },
+        { start_new_l2_to_l1_msgs == 0, "L1 msg stack must be empty" },
 
         { this_call_stack_item.public_inputs.call_context.is_delegate_call == false,
           "Users cannot make a delegatecall" },
diff --git a/circuits/cpp/src/aztec3/circuits/kernel/public/.test.cpp b/circuits/cpp/src/aztec3/circuits/kernel/public/.test.cpp
index d0984dbeb941..c862a970fdf1 100644
--- a/circuits/cpp/src/aztec3/circuits/kernel/public/.test.cpp
+++ b/circuits/cpp/src/aztec3/circuits/kernel/public/.test.cpp
@@ -101,7 +101,7 @@ PublicCallStackItem generate_call_stack_item(NT::fr contract_address, NT::fr msg
     std::array<NT::fr, RETURN_VALUES_LENGTH> return_values = array_of_values<RETURN_VALUES_LENGTH>(count);
     std::array<NT::fr, EMITTED_EVENTS_LENGTH> emitted_events = array_of_values<EMITTED_EVENTS_LENGTH>(count);
     std::array<NT::fr, PUBLIC_CALL_STACK_LENGTH> public_call_stack = array_of_values<PUBLIC_CALL_STACK_LENGTH>(count);
-    std::array<NT::fr, L1_MSG_STACK_LENGTH> l1_msg_stack = array_of_values<L1_MSG_STACK_LENGTH>(count);
+    std::array<NT::fr, NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs = array_of_values<NEW_L2_TO_L1_MSGS_LENGTH>(count);
     std::array<StateRead<NT>, STATE_READS_LENGTH> reads = generate_state_reads(count);
     std::array<StateTransition<NT>, STATE_TRANSITIONS_LENGTH> transitions = generate_state_transitions(count);
 
@@ -114,7 +114,7 @@ PublicCallStackItem generate_call_stack_item(NT::fr contract_address, NT::fr msg
         .state_transitions = transitions,
         .state_reads = reads,
         .public_call_stack = public_call_stack,
-        .l1_msg_stack = l1_msg_stack,
+        .new_l2_to_l1_msgs = new_l2_to_l1_msgs,
 
     };
     PublicCallStackItem call_stack_item = PublicCallStackItem{
@@ -204,7 +204,7 @@ PublicKernelInputsNoPreviousKernel<NT> do_public_call_get_kernel_inputs_no_previ
     std::array<fr, EMITTED_EVENTS_LENGTH> emitted_events = array_of_values<EMITTED_EVENTS_LENGTH>(seed);
     std::array<StateTransition<NT>, STATE_TRANSITIONS_LENGTH> state_transitions = generate_state_transitions(seed);
     std::array<StateRead<NT>, STATE_READS_LENGTH> state_reads = generate_state_reads(seed);
-    std::array<fr, L1_MSG_STACK_LENGTH> l1_msg_stack = array_of_values<L1_MSG_STACK_LENGTH>(seed);
+    std::array<fr, NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs = array_of_values<NEW_L2_TO_L1_MSGS_LENGTH>(seed);
     fr historic_public_data_tree_root = ++seed;
 
     // create the public circuit public inputs
@@ -216,7 +216,7 @@ PublicKernelInputsNoPreviousKernel<NT> do_public_call_get_kernel_inputs_no_previ
         .state_transitions = state_transitions,
         .state_reads = state_reads,
         .public_call_stack = call_stack_hashes,
-        .l1_msg_stack = l1_msg_stack,
+        .new_l2_to_l1_msgs = new_l2_to_l1_msgs,
         .historic_public_data_tree_root = historic_public_data_tree_root,
     };
 
diff --git a/circuits/cpp/src/aztec3/circuits/kernel/public/common.cpp b/circuits/cpp/src/aztec3/circuits/kernel/public/common.cpp
index e1b37cde111c..e28269d80f4a 100644
--- a/circuits/cpp/src/aztec3/circuits/kernel/public/common.cpp
+++ b/circuits/cpp/src/aztec3/circuits/kernel/public/common.cpp
@@ -19,7 +19,7 @@ void common_initialise_end_values(PublicKernelInputs<NT> const& public_kernel_in
 
     end.private_call_stack = start.private_call_stack;
     end.public_call_stack = start.public_call_stack;
-    end.l1_msg_stack = start.l1_msg_stack;
+    end.new_l2_to_l1_msgs = start.new_l2_to_l1_msgs;
 
     end.optionally_revealed_data = start.optionally_revealed_data;
 
diff --git a/circuits/cpp/src/aztec3/circuits/rollup/base/.test.cpp b/circuits/cpp/src/aztec3/circuits/rollup/base/.test.cpp
index 07a205324139..147a7f9eb678 100644
--- a/circuits/cpp/src/aztec3/circuits/rollup/base/.test.cpp
+++ b/circuits/cpp/src/aztec3/circuits/rollup/base/.test.cpp
@@ -575,8 +575,8 @@ TEST_F(base_rollup_tests, native_new_nullifier_tree_double_spend)
 TEST_F(base_rollup_tests, native_empty_block_calldata_hash)
 {
     DummyComposer composer = DummyComposer();
-    // calldata_hash should be computed from leafs of 704 0 bytes. (0x00)
-    std::vector<uint8_t> zero_bytes_vec(704, 0);
+    // calldata_hash should be computed from leafs of 832 0 bytes. (0x00)
+    std::vector<uint8_t> zero_bytes_vec(832, 0);
     auto hash = sha256::sha256(zero_bytes_vec);
     BaseRollupInputs inputs = base_rollup_inputs_from_kernels({ get_empty_kernel(), get_empty_kernel() });
     BaseOrMergeRollupPublicInputs outputs =
@@ -603,48 +603,61 @@ TEST_F(base_rollup_tests, native_calldata_hash)
     // Execute the base rollup circuit with nullifiers, commitments and a contract deployment. Then check the calldata
     // hash against the expected value.
     std::array<PreviousKernelData<NT>, 2> kernel_data = { get_empty_kernel(), get_empty_kernel() };
-    std::vector<uint8_t> input_data(704, 0);
-
-    // Kernel 1
-    // NOTE: nullifier insertions start from 8 as the generate_nullifier_tree_testing_values will populate the every
-    // nullifier leaf
-    for (uint8_t i = 0; i < 4; ++i) {
-        // nullifiers
-        input_data[i * 32 + 31] = i + 8; // 8
-        kernel_data[0].public_inputs.end.new_nullifiers[i] = fr(i + 8);
-
-        // commitments
-        input_data[8 * 32 + i * 32 + 31] = i + 1; // 1
-        kernel_data[0].public_inputs.end.new_commitments[i] = fr(i + 1);
-    }
-    // Kernel 2
-    for (uint8_t i = 0; i < 4; ++i) {
-        // nullifiers
-        input_data[(i + 4) * 32 + 31] = i + 12; // 1
-        kernel_data[1].public_inputs.end.new_nullifiers[i] = fr(i + 12);
-
-        // commitments
-        input_data[8 * 32 + (i + 4) * 32 + 31] = i + 4 + 1; // 1
-        kernel_data[1].public_inputs.end.new_commitments[i] = fr(i + 4 + 1);
-    }
+    std::vector<uint8_t> input_data(832, 0);
 
-    // Add a contract deployment
-    NewContractData<NT> new_contract = {
-        .contract_address = fr(1),
-        .portal_contract_address = fr(3),
-        .function_tree_root = fr(2),
-    };
-    auto contract_leaf = crypto::pedersen_commitment::compress_native(
-        { new_contract.contract_address, new_contract.portal_contract_address, new_contract.function_tree_root },
-        GeneratorIndex::CONTRACT_LEAF);
-    kernel_data[0].public_inputs.end.new_contracts[0] = new_contract;
-    auto contract_leaf_buffer = contract_leaf.to_buffer();
-    auto contract_address_buffer = new_contract.contract_address.to_field().to_buffer();
-    auto portal_address_buffer = new_contract.portal_contract_address.to_field().to_buffer();
-    for (uint8_t i = 0; i < 32; ++i) {
-        input_data[16 * 32 + i] = contract_leaf_buffer[i];
-        input_data[18 * 32 + i] = contract_address_buffer[i];
-        input_data[20 * 32 + i] = portal_address_buffer[i];
+    // @note Should we simply do this outside based on the kernels?
+    for (uint8_t kernel_i = 0; kernel_i < 2; kernel_i++) {
+
+        uint32_t offset = 0;
+        // Nullifiers
+        for (uint8_t j = 0; j < KERNEL_NEW_NULLIFIERS_LENGTH; j++) {
+            uint8_t nullifier = (kernel_i * 4) + j + 16;
+            uint32_t dst = (kernel_i * 4 * 32) + (j * 32) + 31; // only inserting one byte
+            input_data[dst] = nullifier;
+            kernel_data[kernel_i].public_inputs.end.new_nullifiers[j] = nullifier;
+        }
+        offset += KERNEL_NEW_NULLIFIERS_LENGTH * 2 * 32;
+
+        // Commitments
+        for (uint8_t j = 0; j < KERNEL_NEW_COMMITMENTS_LENGTH; j++) {
+            uint8_t commitment = (kernel_i * 4) + j + 32;
+            uint32_t dst = offset + (kernel_i * 4 * 32) + (j * 32) + 31; // only inserting one byte
+            input_data[dst] = commitment;
+            kernel_data[kernel_i].public_inputs.end.new_commitments[j] = commitment;
+        }
+        offset += KERNEL_NEW_COMMITMENTS_LENGTH * 2 * 32;
+
+        // L2 to L1 Messages
+        for (uint8_t j = 0; j < KERNEL_NEW_L2_TO_L1_MSGS_LENGTH; j++) {
+            uint8_t l2_to_l1_message = (kernel_i * 2) + j + 48;
+            uint32_t dst = offset + (kernel_i * 2 * 32) + (j * 32) + 31; // only inserting one byte
+            input_data[dst] = l2_to_l1_message;
+            kernel_data[kernel_i].public_inputs.end.new_l2_to_l1_msgs[j] = l2_to_l1_message;
+        }
+        offset += KERNEL_NEW_L2_TO_L1_MSGS_LENGTH * 2 * 32;
+
+        // Contracts
+        if (kernel_i == 0) {
+            // Contracts
+            NewContractData<NT> new_contract = {
+                .contract_address = fr(1),
+                .portal_contract_address = fr(3),
+                .function_tree_root = fr(2),
+            };
+            auto contract_leaf = crypto::pedersen_commitment::compress_native({ new_contract.contract_address,
+                                                                                new_contract.portal_contract_address,
+                                                                                new_contract.function_tree_root },
+                                                                              GeneratorIndex::CONTRACT_LEAF);
+            auto contract_leaf_buffer = contract_leaf.to_buffer();
+            auto contract_address_buffer = new_contract.contract_address.to_field().to_buffer();
+            auto portal_address_buffer = new_contract.portal_contract_address.to_field().to_buffer();
+            for (uint8_t i = 0; i < 32; ++i) {
+                input_data[offset + kernel_i * 32 + i] = contract_leaf_buffer[i];
+                input_data[offset + kernel_i * 2 * 32 + 2 * 32 + i] = contract_address_buffer[i];
+                input_data[offset + kernel_i * 2 * 32 + 3 * 32 + i] = portal_address_buffer[i];
+            }
+            kernel_data[kernel_i].public_inputs.end.new_contracts[0] = new_contract;
+        }
     }
 
     auto hash = sha256::sha256(input_data);
diff --git a/circuits/cpp/src/aztec3/circuits/rollup/base/native_base_rollup_circuit.cpp b/circuits/cpp/src/aztec3/circuits/rollup/base/native_base_rollup_circuit.cpp
index 10ba6ad70af3..e29591f20436 100644
--- a/circuits/cpp/src/aztec3/circuits/rollup/base/native_base_rollup_circuit.cpp
+++ b/circuits/cpp/src/aztec3/circuits/rollup/base/native_base_rollup_circuit.cpp
@@ -75,25 +75,13 @@ std::vector<NT::fr> calculate_contract_leaves(BaseRollupInputs const& baseRollup
 
     for (size_t i = 0; i < 2; i++) {
 
-        auto new_contacts = baseRollupInputs.kernel_data[i].public_inputs.end.new_contracts;
+        auto new_contracts = baseRollupInputs.kernel_data[i].public_inputs.end.new_contracts;
 
         // loop over the new contracts
         // TODO: NOTE: we are currently assuming that there is only going to be one
-        for (size_t j = 0; j < new_contacts.size(); j++) {
-
-            NT::address contract_address = new_contacts[j].contract_address;
-            NT::address portal_contract_address = new_contacts[j].portal_contract_address;
-            NT::fr function_tree_root = new_contacts[j].function_tree_root;
-
-            // Pedersen hash of the 3 fields (contract_address, portal_contract_address, function_tree_root)
-            auto contract_leaf = crypto::pedersen_commitment::compress_native(
-                { contract_address, portal_contract_address, function_tree_root }, GeneratorIndex::CONTRACT_LEAF);
-
-            // When there is no contract deployment, we should insert a zero leaf into the tree and ignore the
-            // member-ship check. This is to ensure that we don't hit "already deployed" errors when we are not
-            // deploying contracts. e.g., when we are only calling functions on existing contracts.
-            auto to_push = contract_address == NT::address(0) ? NT::fr(0) : contract_leaf;
-
+        for (size_t j = 0; j < new_contracts.size(); j++) {
+            auto leaf_preimage = new_contracts[j];
+            auto to_push = leaf_preimage.contract_address == NT::address(0) ? NT::fr(0) : leaf_preimage.hash();
             contract_leaves.push_back(to_push);
         }
     }
@@ -142,35 +130,64 @@ NT::fr calculate_commitments_subtree(DummyComposer& composer, BaseRollupInputs c
 std::array<NT::fr, 2> calculate_calldata_hash(BaseRollupInputs const& baseRollupInputs,
                                               std::vector<NT::fr> const& contract_leaves)
 {
+
+    /**
+     * @brief Calculate the calldata hash for the base rollup (2 kernels)
+     * Note that the return value is two fields, as the sha256 is 32 bytes and we are using 254 bit field elements.
+     * Essentially, we are computing the hash of the following struct:
+     * Leaf_i = (
+     *    newNullifiersKernel1,
+     *    newNullifiersKernel2,
+     *    newCommitmentsKernel1,
+     *    newCommitmentsKernel2,
+     *    newL2ToL1MsgsKernel1,
+     *    newL2ToL1MsgsKernel2,
+     *    newContractLeafKernel1,
+     *    newContractLeafKernel2,
+     *    newContractDataKernel1.aztecAddress,
+     *    newContractDataKernel1.ethAddress (padded to 32 bytes)
+     *    newContractDataKernel2.aztecAddress,
+     *    newContractDataKernel2.ethAddress (padded to 32 bytes)
+     * );
+     */
     // Compute calldata hashes
-    // 22 = (4 + 4 + 1 + 2) * 2 (2 kernels, 4 nullifiers per kernel, 4 commitments per kernel, 1 contract
-    // deployments, 2 contracts data fields (size 2 for each) )
-    std::array<NT::fr, 22> calldata_hash_inputs;
+    // 26 = (4 + 4 + 2 + 1 + 2) * 2 (2 kernels, 4 nullifiers per kernel, 4 commitments per kernel, 2 l2 to l1_msgs per
+    // kernel, 1 contract deployments, 2 contracts data fields (size 2 for each) )
+    std::array<NT::fr, 26> calldata_hash_inputs;
 
     for (size_t i = 0; i < 2; i++) {
         // Nullifiers
         auto new_nullifiers = baseRollupInputs.kernel_data[i].public_inputs.end.new_nullifiers;
         auto new_commitments = baseRollupInputs.kernel_data[i].public_inputs.end.new_commitments;
+        auto new_l2_to_l1_msgs = baseRollupInputs.kernel_data[i].public_inputs.end.new_l2_to_l1_msgs;
+
+        size_t offset = 0;
+
+        for (size_t j = 0; j < KERNEL_NEW_NULLIFIERS_LENGTH; j++) {
+            calldata_hash_inputs[offset + i * KERNEL_NEW_COMMITMENTS_LENGTH + j] = new_nullifiers[j];
+        }
+        offset += KERNEL_NEW_NULLIFIERS_LENGTH * 2;
+
         for (size_t j = 0; j < KERNEL_NEW_COMMITMENTS_LENGTH; j++) {
-            calldata_hash_inputs[i * KERNEL_NEW_COMMITMENTS_LENGTH + j] = new_nullifiers[j];
-            calldata_hash_inputs[(KERNEL_NEW_NULLIFIERS_LENGTH * 2) + i * KERNEL_NEW_NULLIFIERS_LENGTH + j] =
-                new_commitments[j];
+            calldata_hash_inputs[offset + i * KERNEL_NEW_NULLIFIERS_LENGTH + j] = new_commitments[j];
         }
+        offset += KERNEL_NEW_COMMITMENTS_LENGTH * 2;
 
-        // yuck - TODO: is contract_leaves fixed size?
-        calldata_hash_inputs[16 + i] = contract_leaves[i];
+        for (size_t j = 0; j < KERNEL_NEW_L2_TO_L1_MSGS_LENGTH; j++) {
+            calldata_hash_inputs[offset + i * KERNEL_NEW_L2_TO_L1_MSGS_LENGTH + j] = new_l2_to_l1_msgs[j];
+        }
+        offset += KERNEL_NEW_L2_TO_L1_MSGS_LENGTH * 2;
 
-        auto new_contracts = baseRollupInputs.kernel_data[i].public_inputs.end.new_contracts;
+        calldata_hash_inputs[offset + i] = contract_leaves[i];
+        offset += KERNEL_NEW_CONTRACTS_LENGTH * 2;
 
-        // TODO: this assumes that there is only one contract deployment
-        calldata_hash_inputs[18 + i] = new_contracts[0].contract_address;
-        calldata_hash_inputs[20 + i] = new_contracts[0].portal_contract_address;
+        auto new_contracts = baseRollupInputs.kernel_data[i].public_inputs.end.new_contracts;
+        calldata_hash_inputs[offset + i * 2] = new_contracts[0].contract_address;
+        calldata_hash_inputs[offset + i * 2 + 1] = new_contracts[0].portal_contract_address;
     }
 
-    // FIXME
-    // Calculate sha256 hash of calldata; TODO: work out typing here
-    // 22 * 32 = 22 fields, each 32 bytes
-    std::array<uint8_t, 22 * 32> calldata_hash_inputs_bytes;
+    // 26 * 32 = 26 fields, each 32 bytes
+    std::array<uint8_t, 26 * 32> calldata_hash_inputs_bytes;
     // Convert all into a buffer, then copy into the array, then hash
     for (size_t i = 0; i < calldata_hash_inputs.size(); i++) {
         auto as_bytes = calldata_hash_inputs[i].to_buffer();
@@ -178,7 +195,7 @@ std::array<NT::fr, 2> calculate_calldata_hash(BaseRollupInputs const& baseRollup
         auto offset = i * 32;
         std::copy(as_bytes.begin(), as_bytes.end(), calldata_hash_inputs_bytes.begin() + offset);
     }
-    // TODO: double check this gpt code
+
     std::vector<uint8_t> calldata_hash_inputs_bytes_vec(calldata_hash_inputs_bytes.begin(),
                                                         calldata_hash_inputs_bytes.end());
 
diff --git a/circuits/cpp/src/aztec3/circuits/rollup/merge/.test.cpp b/circuits/cpp/src/aztec3/circuits/rollup/merge/.test.cpp
index 8a3fa7a42082..288d26dc8416 100644
--- a/circuits/cpp/src/aztec3/circuits/rollup/merge/.test.cpp
+++ b/circuits/cpp/src/aztec3/circuits/rollup/merge/.test.cpp
@@ -215,7 +215,7 @@ TEST_F(merge_rollup_tests, native_start_and_end_snapshots)
 TEST_F(merge_rollup_tests, native_calldata_hash)
 {
     DummyComposer composer = DummyComposer();
-    std::vector<uint8_t> zero_bytes_vec(704, 0);
+    std::vector<uint8_t> zero_bytes_vec(832, 0);
     auto call_data_hash_inner = sha256::sha256(zero_bytes_vec);
 
     std::array<uint8_t, 64> hash_input;
diff --git a/circuits/cpp/src/aztec3/circuits/rollup/root/.test.cpp b/circuits/cpp/src/aztec3/circuits/rollup/root/.test.cpp
index 7f0f3eaaa98f..f2f3a8ce7955 100644
--- a/circuits/cpp/src/aztec3/circuits/rollup/root/.test.cpp
+++ b/circuits/cpp/src/aztec3/circuits/rollup/root/.test.cpp
@@ -77,8 +77,10 @@ using aztec3::circuits::apps::test_apps::escrow::deposit;
 using aztec3::circuits::kernel::private_kernel::utils::dummy_previous_kernel;
 using aztec3::circuits::mock::mock_kernel_circuit;
 using aztec3::circuits::rollup::test_utils::utils::get_empty_kernel;
+using aztec3::circuits::rollup::test_utils::utils::get_initial_nullifier_tree;
 using aztec3::circuits::rollup::test_utils::utils::get_root_rollup_inputs;
 using aztec3::circuits::rollup::test_utils::utils::set_kernel_commitments;
+using aztec3::circuits::rollup::test_utils::utils::set_kernel_l2_to_l1_msgs;
 using aztec3::circuits::rollup::test_utils::utils::set_kernel_nullifiers;
 // using aztec3::circuits::mock::mock_kernel_inputs;
 
@@ -166,7 +168,7 @@ class root_rollup_tests : public ::testing::Test {
 
 TEST_F(root_rollup_tests, native_calldata_hash_empty_blocks)
 {
-    std::vector<uint8_t> zero_bytes_vec(704, 0);
+    std::vector<uint8_t> zero_bytes_vec(832, 0);
     auto call_data_hash_inner = sha256::sha256(zero_bytes_vec);
 
     std::array<uint8_t, 64> hash_input;
@@ -201,7 +203,8 @@ TEST_F(root_rollup_tests, native_calldata_hash_empty_blocks)
     EXPECT_FALSE(composer.failed());
 
     // Expected hash of public inputs for an empty L2 block. Also used in the contract tests.
-    fr expected_hash = uint256_t("0013b2202a3e48b039cda7eef0976060d86e610d77fc9bb8cd5b0f1b561df48c");
+    // Can be computed using the typescript l2_block's helper functions (see circuit_block_builder.test.ts)
+    fr expected_hash = uint256_t("2b9b56549c50cad1f6329a594979cf9a1d71f87f24c2a1bf33fe7743faabaaeb");
     ASSERT_EQ(outputs.hash(), expected_hash);
 
     run_cbind(inputs, outputs, true);
@@ -209,6 +212,7 @@ TEST_F(root_rollup_tests, native_calldata_hash_empty_blocks)
 
 TEST_F(root_rollup_tests, native_root_missing_nullifier_logic)
 {
+    // Creates the same block as we have for solidity tests and in typescript.
     utils::DummyComposer composer = utils::DummyComposer();
 
     MemoryTree data_tree = MemoryTree(PRIVATE_DATA_TREE_HEIGHT);
@@ -224,36 +228,44 @@ TEST_F(root_rollup_tests, native_root_missing_nullifier_logic)
         get_empty_kernel(), get_empty_kernel(), get_empty_kernel(), get_empty_kernel()
     };
 
-    // Create commitments
-    for (uint8_t kernel_j = 0; kernel_j < 4; kernel_j++) {
-        std::array<fr, KERNEL_NEW_COMMITMENTS_LENGTH> new_commitments;
-        for (uint8_t commitment_k = 0; commitment_k < KERNEL_NEW_COMMITMENTS_LENGTH; commitment_k++) {
-            auto val = fr(kernel_j * KERNEL_NEW_COMMITMENTS_LENGTH + commitment_k + 1);
-            new_commitments[commitment_k] = val;
-            data_tree.update_element(kernel_j * KERNEL_NEW_COMMITMENTS_LENGTH + commitment_k, val);
-        }
-        set_kernel_commitments(kernels[kernel_j], new_commitments);
+    set_kernel_commitments(kernels[0], { 257, 258, 259, 260 });
+    for (size_t i = 0; i < 4; i++) {
+        data_tree.update_element(i, 257 + i);
+    }
+
+    set_kernel_nullifiers(kernels[0], { 513, 514, 515, 516 });
+    auto nullifier_tree = get_initial_nullifier_tree({ 1, 2, 3, 4, 5, 6, 7 });
+    for (size_t i = 0; i < 4; i++) {
+        nullifier_tree.update_element(513 + i);
     }
 
-    // TODO: Add nullifiers
+    set_kernel_l2_to_l1_msgs(kernels[0], { 1281, 1282 });
+
+    /*std::vector<uint8_t> buffer = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x01,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
+    0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x03 };
+    // Initialize a pointer to the start of the buffer
+    uint8_t const* it = buffer.data();
+    // Initialize a ContractData object
+    NewContractData<NT> new_contract_data;
+    // Read data from the buffer into the ContractData object
+    read(it, new_contract_data);
+    info(new_contract_data, " -> ", new_contract_data.hash());*/
 
-    // Contract tree
     NewContractData<NT> new_contract = {
-        .contract_address = fr(1),
-        .portal_contract_address = fr(3),
-        .function_tree_root = fr(2),
+        .contract_address = fr(1537),
+        .portal_contract_address = uint256_t("0000000000000000000000000202020202020202020202020202020202020202"),
+        .function_tree_root = fr(1539),
     };
-    auto contract_leaf = crypto::pedersen_commitment::compress_native(
-        {
-            new_contract.contract_address,
-            new_contract.portal_contract_address,
-            new_contract.function_tree_root,
-        },
-        GeneratorIndex::CONTRACT_LEAF);
-
-    // Update contract tree
-    contract_tree.update_element(2, contract_leaf);
-    kernels[2].public_inputs.end.new_contracts[0] = new_contract;
+
+    // todo: Something is not right down here. I'm getting different hashes on same leaf preimage
+    info("contract: ", new_contract.hash());
+
+    contract_tree.update_element(0, new_contract.hash());
+    kernels[0].public_inputs.end.new_contracts[0] = new_contract;
 
     // The start historic data snapshot
     AppendOnlyTreeSnapshot<NT> start_historic_data_tree_snapshot = { .root = historic_data_tree.root(),
@@ -275,6 +287,10 @@ TEST_F(root_rollup_tests, native_root_missing_nullifier_logic)
     RootRollupPublicInputs outputs =
         aztec3::circuits::rollup::native_root_rollup::root_rollup_circuit(composer, rootRollupInputs);
 
+    // info(outputs);
+    info("public output hash: ", outputs.hash());
+    info("root: ", contract_tree.root());
+
     // Check data trees
     ASSERT_EQ(
         outputs.start_private_data_tree_snapshot,
@@ -286,6 +302,9 @@ TEST_F(root_rollup_tests, native_root_missing_nullifier_logic)
                                                                .next_available_leaf_index = 16 };
     ASSERT_EQ(outputs.end_private_data_tree_snapshot, expected_data_tree_snapshot);
 
+    // Something wrong with contract tree? 0xf0c1d03ac280b15abbdfa91faa6137b216b9c29d83d30c1c9ce925ad4379fa6
+    // Why are we getting things that is so different from typescript?
+
     // check contract trees
     ASSERT_EQ(outputs.start_contract_tree_snapshot,
               rootRollupInputs.previous_rollup_data[0].base_or_merge_rollup_public_inputs.start_contract_tree_snapshot);
@@ -305,6 +324,9 @@ TEST_F(root_rollup_tests, native_root_missing_nullifier_logic)
     ASSERT_EQ(outputs.start_tree_of_historic_contract_tree_roots_snapshot, start_historic_contract_tree_snapshot);
     ASSERT_EQ(outputs.end_tree_of_historic_contract_tree_roots_snapshot, end_historic_contract_tree_snapshot);
 
+    fr expected = uint256_t("20638cd5e03d287dbd356af6e16fd852337f535b12d06f7266599c035696098d");
+    ASSERT_EQ(outputs.hash(), expected);
+
     EXPECT_FALSE(composer.failed());
 }
 
diff --git a/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.cpp b/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.cpp
index 693184d71992..8cf7316f063b 100644
--- a/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.cpp
+++ b/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.cpp
@@ -67,6 +67,15 @@ void set_kernel_commitments(KernelData& kernel_data, std::array<fr, KERNEL_NEW_C
     }
 }
 
+void set_kernel_l2_to_l1_msgs(KernelData& kernel_data,
+                              std::array<fr, KERNEL_NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs)
+{
+    for (size_t i = 0; i < KERNEL_NEW_L2_TO_L1_MSGS_LENGTH; i++) {
+        kernel_data.public_inputs.end.new_l2_to_l1_msgs[i] = new_l2_to_l1_msgs[i];
+    }
+}
+
+
 BaseRollupInputs base_rollup_inputs_from_kernels(std::array<KernelData, 2> kernel_data,
                                                  MerkleTree& private_data_tree,
                                                  MerkleTree& contract_tree,
@@ -242,10 +251,9 @@ std::array<PreviousRollupData<NT>, 2> get_previous_rollup_data(DummyComposer& co
                                              kernel_data[i].public_inputs.end.new_commitments[j]);
         }
         auto contract_data = kernel_data[i].public_inputs.end.new_contracts[0];
-        auto contract_leaf = crypto::pedersen_commitment::compress_native(
-            { contract_data.contract_address, contract_data.portal_contract_address, contract_data.function_tree_root },
-            GeneratorIndex::CONTRACT_LEAF);
-        contract_tree.update_element(i, contract_leaf);
+        if (contract_data.contract_address != 0) {
+            contract_tree.update_element(i, contract_data.hash());
+        }
         for (size_t j = 0; j < KERNEL_NEW_NULLIFIERS_LENGTH; j++) {
             initial_values.push_back(kernel_data[i].public_inputs.end.new_nullifiers[j]);
             nullifiers[i * KERNEL_NEW_NULLIFIERS_LENGTH + j] = kernel_data[2 + i].public_inputs.end.new_nullifiers[j];
@@ -263,7 +271,7 @@ std::array<PreviousRollupData<NT>, 2> get_previous_rollup_data(DummyComposer& co
     // @todo Need an additional tests to check that these below are correct.
     // Changing the index in private tree still pass tests etc (16).
     base_rollup_input_2.new_contracts_subtree_sibling_path =
-        get_sibling_path<CONTRACT_SUBTREE_INCLUSION_CHECK_DEPTH>(contract_tree, 1, CONTRACT_SUBTREE_DEPTH);
+        get_sibling_path<CONTRACT_SUBTREE_INCLUSION_CHECK_DEPTH>(contract_tree, 2, CONTRACT_SUBTREE_DEPTH);
     base_rollup_input_2.new_commitments_subtree_sibling_path =
         get_sibling_path<PRIVATE_DATA_SUBTREE_INCLUSION_CHECK_DEPTH>(private_data_tree, 8, PRIVATE_DATA_SUBTREE_DEPTH);
 
diff --git a/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.hpp b/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.hpp
index b1a237487522..baaa42799e60 100644
--- a/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.hpp
+++ b/circuits/cpp/src/aztec3/circuits/rollup/test_utils/utils.hpp
@@ -48,15 +48,11 @@ template <size_t N>
 std::array<fr, N> get_sibling_path(MerkleTree& tree, size_t leafIndex, size_t const& subtree_depth_to_skip)
 {
     std::array<fr, N> siblingPath;
-    auto path = tree.get_hash_path(leafIndex);
+    auto path = tree.get_sibling_path(leafIndex);
     // slice out the skip
     leafIndex = leafIndex >> (subtree_depth_to_skip);
     for (size_t i = 0; i < N; i++) {
-        if (leafIndex & (1 << i)) {
-            siblingPath[i] = path[subtree_depth_to_skip + i].first;
-        } else {
-            siblingPath[i] = path[subtree_depth_to_skip + i].second;
-        }
+        siblingPath[i] = path[subtree_depth_to_skip + i];
     }
     return siblingPath;
 }
@@ -99,6 +95,9 @@ void set_kernel_commitments(KernelData& kernel_data, std::array<fr, KERNEL_NEW_C
 
 void set_kernel_nullifiers(KernelData& kernel_data, std::array<fr, KERNEL_NEW_NULLIFIERS_LENGTH> new_nullifiers);
 
+void set_kernel_l2_to_l1_msgs(KernelData& kernel_data,
+                              std::array<fr, KERNEL_NEW_L2_TO_L1_MSGS_LENGTH> new_l2_to_l1_msgs);
+
 MergeRollupInputs get_merge_rollup_inputs(utils::DummyComposer& composer, std::array<KernelData, 4> kernel_data);
 
 inline abis::PublicDataWrite<NT> make_public_write(fr leaf_index, fr old_value, fr new_value)
diff --git a/circuits/cpp/src/aztec3/constants.hpp b/circuits/cpp/src/aztec3/constants.hpp
index b961b50eeab4..e010eae9c8dc 100644
--- a/circuits/cpp/src/aztec3/constants.hpp
+++ b/circuits/cpp/src/aztec3/constants.hpp
@@ -10,20 +10,20 @@ constexpr size_t EMITTED_EVENTS_LENGTH = 4;
 
 constexpr size_t NEW_COMMITMENTS_LENGTH = 4;
 constexpr size_t NEW_NULLIFIERS_LENGTH = 4;
+constexpr size_t NEW_L2_TO_L1_MSGS_LENGTH = 2;
 
 constexpr size_t STATE_TRANSITIONS_LENGTH = 4;
 constexpr size_t STATE_READS_LENGTH = 4;
 
 constexpr size_t PRIVATE_CALL_STACK_LENGTH = 4;
 constexpr size_t PUBLIC_CALL_STACK_LENGTH = 4;
-constexpr size_t L1_MSG_STACK_LENGTH = 2;
 
 constexpr size_t KERNEL_NEW_COMMITMENTS_LENGTH = 4;
 constexpr size_t KERNEL_NEW_NULLIFIERS_LENGTH = 4;
+constexpr size_t KERNEL_NEW_L2_TO_L1_MSGS_LENGTH = 2;
 constexpr size_t KERNEL_NEW_CONTRACTS_LENGTH = 1;
 constexpr size_t KERNEL_PRIVATE_CALL_STACK_LENGTH = 8;
 constexpr size_t KERNEL_PUBLIC_CALL_STACK_LENGTH = 8;
-constexpr size_t KERNEL_L1_MSG_STACK_LENGTH = 4;
 constexpr size_t KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH = 4;
 
 constexpr size_t VK_TREE_HEIGHT = 3;
diff --git a/l1-contracts/src/core/Decoder.sol b/l1-contracts/src/core/Decoder.sol
index 9ee67b693dce..a025cc163f75 100644
--- a/l1-contracts/src/core/Decoder.sol
+++ b/l1-contracts/src/core/Decoder.sol
@@ -40,15 +40,19 @@ pragma solidity >=0.8.18;
  *  | 0x170                    | x          | newCommits
  *  | 0x170 + x                | 0x04       | len(newNullifiers) denoted y
  *  | 0x174 + x                | y          | newNullifiers
- *  | 0x174 + x + y            | 0x04       | len(newContracts) denoted z
- *  | 0x178 + x + y            | z          | newContracts
- *  | 0x178 + x + y + z        | z          | newContractData
+ *  | 0x174 + x + y            | 0x04       | len(newL2ToL1msgs) denoted z
+ *  | 0x178 + x + y            | z          | newL2ToL1msgs
+ *  | 0x178 + x + y + z        | 0x04       | len(newContracts) denoted v
+ *  | 0x17c + x + y + z        | v          | newContracts
+ *  | 0x17c + x + y + z + v    | v          | newContractData
  *  |---                       |---         | ---
- *
+ * TODO: Actually the byte start are not with x,y,z,v but multiplied by the size... of the types most are 32 bytes
+ * but newContractData is 52 bytes.
  */
 contract Decoder {
   uint256 internal constant COMMITMENTS_PER_KERNEL = 4;
   uint256 internal constant NULLIFIERS_PER_KERNEL = 4;
+  uint256 internal constant L2_TO_L1_MSGS_PER_KERNEL = 2;
 
   // Prime field order
   uint256 internal constant P =
@@ -58,8 +62,8 @@ contract Decoder {
    * @notice Decodes the inputs and computes values to check state against
    * @param _l2Block - The L2 block calldata.
    * @return l2BlockNumber  - The L2 block number.
-   * @return oldStateHash - The state hash expected prior the execution.
-   * @return newStateHash - The state hash expected after the execution.
+   * @return startStateHash - The state hash expected prior the execution.
+   * @return endStateHash - The state hash expected after the execution.
    * @return publicInputHash - The hash of the public inputs
    */
   function _decode(bytes calldata _l2Block)
@@ -67,16 +71,16 @@ contract Decoder {
     pure
     returns (
       uint256 l2BlockNumber,
-      bytes32 oldStateHash,
-      bytes32 newStateHash,
+      bytes32 startStateHash,
+      bytes32 endStateHash,
       bytes32 publicInputHash
     )
   {
     l2BlockNumber = _getL2BlockNumber(_l2Block);
-    // Note, for oldStateHash to match the storage, the l2 block number must be new - 1.
+    // Note, for startStateHash to match the storage, the l2 block number must be new - 1.
     // Only jumping 1 block at a time.
-    oldStateHash = _computeStateHash(l2BlockNumber - 1, 0x4, _l2Block);
-    newStateHash = _computeStateHash(l2BlockNumber, 0xb8, _l2Block);
+    startStateHash = _computeStateHash(l2BlockNumber - 1, 0x4, _l2Block);
+    endStateHash = _computeStateHash(l2BlockNumber, 0xb8, _l2Block);
     publicInputHash = _computePublicInputsHash(_l2Block);
   }
 
@@ -142,6 +146,8 @@ contract Decoder {
 
   struct Vars {
     uint256 commitmentCount;
+    uint256 nullifierCount;
+    uint256 l2ToL1msgCount;
     uint256 kernelCount;
     uint256 contractCount;
   }
@@ -155,19 +161,37 @@ contract Decoder {
     Vars memory vars;
     {
       uint256 commitmentCount;
+      uint256 nullifierCount;
+      uint256 l2ToL1msgCount;
       assembly {
         commitmentCount := and(shr(224, calldataload(add(_l2Block.offset, 0x16c))), 0xffffffff)
+        nullifierCount :=
+          and(
+            shr(224, calldataload(add(_l2Block.offset, add(0x170, mul(commitmentCount, 0x20))))),
+            0xffffffff
+          )
+        l2ToL1msgCount :=
+          and(
+            shr(
+              224,
+              calldataload(
+                add(_l2Block.offset, add(0x174, mul(add(nullifierCount, commitmentCount), 0x20)))
+              )
+            ),
+            0xffffffff
+          )
       }
       vars.commitmentCount = commitmentCount;
+      vars.nullifierCount = nullifierCount;
+      vars.l2ToL1msgCount = l2ToL1msgCount;
       vars.kernelCount = commitmentCount / COMMITMENTS_PER_KERNEL;
       uint256 contractCountOffset =
-        vars.kernelCount * (COMMITMENTS_PER_KERNEL + NULLIFIERS_PER_KERNEL) * 0x20;
-
+        (vars.commitmentCount + vars.nullifierCount + vars.l2ToL1msgCount) * 0x20;
       uint256 newContractCount;
       assembly {
         newContractCount :=
           and(
-            shr(224, calldataload(add(_l2Block.offset, add(0x174, contractCountOffset)))), 0xffffffff
+            shr(224, calldataload(add(_l2Block.offset, add(0x178, contractCountOffset)))), 0xffffffff
           )
       }
       vars.contractCount = newContractCount;
@@ -175,13 +199,10 @@ contract Decoder {
 
     bytes32[] memory baseLeafs = new bytes32[](vars.kernelCount / 2);
 
-    uint256 dstCommitmentOffset = COMMITMENTS_PER_KERNEL * 0x20 * 0x2;
-    uint256 dstContractOffset = dstCommitmentOffset + NULLIFIERS_PER_KERNEL * 0x20 * 0x2;
-
     uint256 srcCommitmentOffset = 0x170;
-    uint256 srcNullifierOffset = 0x174 + vars.commitmentCount * 0x20;
-    uint256 srcContractOffset =
-      0x178 + (baseLeafs.length * 2 * (NULLIFIERS_PER_KERNEL + COMMITMENTS_PER_KERNEL) * 0x20);
+    uint256 srcNullifierOffset = srcCommitmentOffset + 0x4 + vars.commitmentCount * 0x20;
+    uint256 srcL2ToL1msgOffset = srcNullifierOffset + 0x4 + vars.nullifierCount * 0x20;
+    uint256 srcContractOffset = srcL2ToL1msgOffset + 0x4 + vars.l2ToL1msgCount * 0x20;
     uint256 srcContractDataOffset = srcContractOffset + vars.contractCount * 0x20;
 
     for (uint256 i = 0; i < baseLeafs.length; i++) {
@@ -192,6 +213,8 @@ contract Decoder {
        *    newNullifiersKernel2,
        *    newCommitmentsKernel1,
        *    newCommitmentsKernel2,
+       *    newL2ToL1MsgsKernel1,
+       *    newL2ToL1MsgsKernel2,
        *    newContractLeafKernel1,
        *    newContractLeafKernel2,
        *    newContractDataKernel1.aztecAddress,
@@ -202,47 +225,66 @@ contract Decoder {
        * Note that we always read data, the l2Block (atm) must therefore include dummy or zero-notes for
        * Zero values.
        */
-      bytes memory baseLeaf = new bytes(0x2c0);
+      bytes memory baseLeaf = new bytes(0x340);
 
       assembly {
         // Adding new nullifiers
         calldatacopy(add(baseLeaf, 0x20), add(_l2Block.offset, srcNullifierOffset), mul(0x08, 0x20))
 
         // Adding new commitments
+        let dstCommitmentOffset := mul(0x20, 0x08)
         calldatacopy(
           add(baseLeaf, add(0x20, dstCommitmentOffset)),
           add(_l2Block.offset, srcCommitmentOffset),
           mul(0x08, 0x20)
         )
 
+        // Adding new L2ToL1Msgs
+        let dstL2ToL1msgOffset := add(dstCommitmentOffset, mul(0x20, 0x8))
+        calldatacopy(
+          add(baseLeaf, add(0x20, dstL2ToL1msgOffset)),
+          add(_l2Block.offset, srcL2ToL1msgOffset),
+          mul(0x04, 0x20)
+        )
+
         // Adding Contract Leafs
+        let dstContractOffset := add(dstL2ToL1msgOffset, mul(0x20, 0x4))
         calldatacopy(
           add(baseLeaf, add(0x20, dstContractOffset)),
           add(_l2Block.offset, srcContractOffset),
           mul(2, 0x20)
         )
+        dstContractOffset := add(dstContractOffset, 0x40)
 
         // Kernel1.contract.aztecaddress
         calldatacopy(
-          add(baseLeaf, add(0x20, add(dstContractOffset, 0x40))),
+          add(baseLeaf, add(0x20, dstContractOffset)),
           add(_l2Block.offset, srcContractDataOffset),
           0x20
         )
+        dstContractOffset := add(dstContractOffset, 0x20)
+
         // Kernel1.contract.ethAddress padded to 32 bytes
+        dstContractOffset := add(dstContractOffset, 0xc)
         calldatacopy(
-          add(baseLeaf, add(0x20, add(dstContractOffset, 0x6c))),
+          add(baseLeaf, add(0x20, dstContractOffset)),
           add(_l2Block.offset, add(srcContractDataOffset, 0x20)),
           0x14
         )
+        dstContractOffset := add(dstContractOffset, 0x20)
+
         // Kernel2.contract.aztecaddress
         calldatacopy(
-          add(baseLeaf, add(0x20, add(dstContractOffset, 0x80))),
+          add(baseLeaf, add(0x20, dstContractOffset)),
           add(_l2Block.offset, add(srcContractDataOffset, 0x34)),
           0x20
         )
+        dstContractOffset := add(dstContractOffset, 0x20)
+
         // Kernel2.contract.ethAddress padded to 32 bytes
+        dstContractOffset := add(dstContractOffset, 0xc)
         calldatacopy(
-          add(baseLeaf, add(0x20, add(dstContractOffset, 0xac))),
+          add(baseLeaf, add(0x20, dstContractOffset)),
           add(_l2Block.offset, add(srcContractDataOffset, 0x54)),
           0x14
         )
@@ -250,6 +292,7 @@ contract Decoder {
 
       srcCommitmentOffset += 2 * COMMITMENTS_PER_KERNEL * 0x20;
       srcNullifierOffset += 2 * NULLIFIERS_PER_KERNEL * 0x20;
+      srcL2ToL1msgOffset += 2 * L2_TO_L1_MSGS_PER_KERNEL * 0x20;
       srcContractOffset += 2 * 0x20;
       srcContractDataOffset += 2 * 0x34;
 
diff --git a/l1-contracts/src/core/Rollup.sol b/l1-contracts/src/core/Rollup.sol
index 4b1653020546..e09b66b98c2c 100644
--- a/l1-contracts/src/core/Rollup.sol
+++ b/l1-contracts/src/core/Rollup.sol
@@ -31,12 +31,12 @@ contract Rollup is Decoder {
    * @param _l2Block - The L2Block data, formatted as outlined in `Decoder.sol`
    */
   function process(bytes memory _proof, bytes calldata _l2Block) external {
-    (uint256 l2BlockNumber, bytes32 oldStateHash, bytes32 newStateHash, bytes32 publicInputHash) =
+    (uint256 l2BlockNumber, bytes32 startStateHash, bytes32 endStateHash, bytes32 publicInputHash) =
       _decode(_l2Block);
 
     // @todo Proper genesis state. If the state is empty, we allow anything for now.
-    if (rollupStateHash != bytes32(0) && rollupStateHash != oldStateHash) {
-      revert InvalidStateHash(rollupStateHash, oldStateHash);
+    if (rollupStateHash != bytes32(0) && rollupStateHash != startStateHash) {
+      revert InvalidStateHash(rollupStateHash, startStateHash);
     }
 
     bytes32[] memory publicInputs = new bytes32[](1);
@@ -46,7 +46,7 @@ contract Rollup is Decoder {
       revert InvalidProof();
     }
 
-    rollupStateHash = newStateHash;
+    rollupStateHash = endStateHash;
 
     emit L2BlockProcessed(l2BlockNumber);
   }
diff --git a/l1-contracts/src/periphery/UnverifiedDataEmitter.sol b/l1-contracts/src/periphery/UnverifiedDataEmitter.sol
index 8933f1157d6e..c0285c221ada 100644
--- a/l1-contracts/src/periphery/UnverifiedDataEmitter.sol
+++ b/l1-contracts/src/periphery/UnverifiedDataEmitter.sol
@@ -13,7 +13,12 @@ contract UnverifiedDataEmitter {
    * @param portalAddress - The address of the L1 counterparty
    * @param acir - The acir bytecode of the L2 contract
    */
-  event ContractDeployment(uint256 indexed l2BlockNum, bytes32 indexed aztecAddress, address indexed portalAddress, bytes acir);
+  event ContractDeployment(
+    uint256 indexed l2BlockNum,
+    bytes32 indexed aztecAddress,
+    address indexed portalAddress,
+    bytes acir
+  );
 
   /**
    * @notice Used to share data which are not required to advance the state but are needed for other purposes
diff --git a/l1-contracts/test/Decoder.t.sol b/l1-contracts/test/Decoder.t.sol
index 5efef377203d..c0582e5d27c8 100644
--- a/l1-contracts/test/Decoder.t.sol
+++ b/l1-contracts/test/Decoder.t.sol
@@ -20,45 +20,176 @@ contract DecodeHelper is Decoder {
   }
 }
 
-// Blocks generated with https://gist.github.com/LHerskind/dccc762ee539b7b0984bf51af6f51dbb
+// Blocks generated using `circuit_block_builder.test.ts`
 contract DecoderTest is Test {
   Rollup internal rollup;
   DecodeHelper internal helper;
 
   bytes block_1 =
-    hex"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+    hex"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";
   bytes block_2 =
-    hex"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";
+    hex"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";
 
-  bytes block_empty =
-    hex"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";
+  bytes block_empty_1 =
+    hex"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";
+
+  bytes block_empty_2 =
+    hex"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";
 
   function setUp() public {
     rollup = new Rollup();
     helper = new DecodeHelper();
   }
 
-  function testDecoderDiffRoot() public {
-    bytes32 diffRoot = helper.computeDiffRoot(block_1);
-    assertEq(
-      0x260777a20fee44e43d74c60350ebb7a631dabe0a8a1c27ee9a8264b2f5c24c2d,
-      diffRoot,
-      "Invalid diff root"
-    );
-  }
+  function testEmptyBlocks() public {
+    {
+      bytes32 diffRoot = helper.computeDiffRoot(block_empty_1);
+      assertEq(
+        0x5064e7b73cbb2cf66cecd9ee874d30cc654bda2fba26ad1c75f0c9db437b261b,
+        diffRoot,
+        "Invalid diff root"
+      );
+
+      (
+        uint256 l2BlockNumber,
+        bytes32 startStateHash,
+        bytes32 endStateHash,
+        bytes32 publicInputsHash
+      ) = helper.decode(block_empty_1);
+
+      assertEq(l2BlockNumber, 1, "Invalid block number");
+      assertEq(
+        startStateHash,
+        0xd3f7645c4b49d31bca62aca09aa26740d7e47d264f3021e2de2db40562944745,
+        "Invalid start state hash"
+      );
+      assertEq(
+        endStateHash,
+        0x285c26b176e983e6a9101b2c9cb103771b0aedae57df63600631fed28ea7461d,
+        "Invalid end state hash"
+      );
+      assertEq(
+        publicInputsHash,
+        0x2b9b56549c50cad1f6329a594979cf9a1d71f87f24c2a1bf33fe7743faabaaeb,
+        "Invalid public input hash"
+      );
+
+      rollup.process(bytes(""), block_empty_1);
+
+      assertEq(rollup.rollupStateHash(), endStateHash, "Invalid rollup state hash");
+    }
+
+    {
+      bytes32 diffRoot = helper.computeDiffRoot(block_empty_2);
+      assertEq(
+        0x5064e7b73cbb2cf66cecd9ee874d30cc654bda2fba26ad1c75f0c9db437b261b,
+        diffRoot,
+        "Invalid diff root"
+      );
+
+      (
+        uint256 l2BlockNumber,
+        bytes32 startStateHash,
+        bytes32 endStateHash,
+        bytes32 publicInputsHash
+      ) = helper.decode(block_empty_2);
+
+      assertEq(l2BlockNumber, 2, "Invalid block number");
+      assertEq(
+        startStateHash,
+        0x285c26b176e983e6a9101b2c9cb103771b0aedae57df63600631fed28ea7461d,
+        "Invalid start state hash"
+      );
+      assertEq(
+        endStateHash,
+        0xa98e86cafb947da8469576e685c76b7b7451f72e8ff6c0e72c67d5bac6942b21,
+        "Invalid end state hash"
+      );
+      assertEq(
+        publicInputsHash,
+        0x0fb6d019d1da49d67732e9ca797f83777f09e50777cb4d08f46865b01be85881,
+        "Invalid public input hash"
+      );
+
+      rollup.process(bytes(""), block_empty_2);
 
-  function testDecoder() public {
-    rollup.process(bytes(""), block_1);
-    rollup.process(bytes(""), block_2);
+      assertEq(rollup.rollupStateHash(), endStateHash, "Invalid rollup state hash");
+    }
   }
 
-  function testPublicInputHash() public {
-    (uint256 l2BlockNumber, bytes32 oldStateHash, bytes32 newStateHash, bytes32 publicInputsHash) =
-      helper.decode(block_empty);
-    assertEq(
-      publicInputsHash,
-      0x0013b2202a3e48b039cda7eef0976060d86e610d77fc9bb8cd5b0f1b561df48c,
-      "Invalid public input hash"
-    );
+  function testNonEmptyBlocks() public {
+    {
+      bytes32 diffRoot = helper.computeDiffRoot(block_1);
+      assertEq(
+        0x9f1a00d7220a2b51a9c2591c2f85e089f03d06b01138586ea5e3656435d5e749,
+        diffRoot,
+        "Invalid diff root block 1"
+      );
+
+      (
+        uint256 l2BlockNumber,
+        bytes32 startStateHash,
+        bytes32 endStateHash,
+        bytes32 publicInputsHash
+      ) = helper.decode(block_1);
+
+      assertEq(l2BlockNumber, 1, "Invalid block number");
+      assertEq(
+        startStateHash,
+        0xd3f7645c4b49d31bca62aca09aa26740d7e47d264f3021e2de2db40562944745,
+        "Invalid start state hash block 1"
+      );
+      assertEq(
+        endStateHash,
+        0xe3b20add23469bcbf25157ff75b81665564b089aa95083f8e095a3bb77062831,
+        "Invalid end state hash block 1"
+      );
+      assertEq(
+        publicInputsHash,
+        0x20638cd5e03d287dbd356af6e16fd852337f535b12d06f7266599c035696098d,
+        "Invalid public input hash block 1"
+      );
+
+      rollup.process(bytes(""), block_1);
+
+      assertEq(rollup.rollupStateHash(), endStateHash, "Invalid rollup state hash block 1");
+    }
+
+    {
+      bytes32 diffRoot = helper.computeDiffRoot(block_2);
+      assertEq(
+        0x50f2f2dc986fc4022b8fdde8f2d610c82ee36776b282ca3514c12726dd9081ef,
+        diffRoot,
+        "Invalid diff root block 2"
+      );
+
+      (
+        uint256 l2BlockNumber,
+        bytes32 startStateHash,
+        bytes32 endStateHash,
+        bytes32 publicInputsHash
+      ) = helper.decode(block_2);
+
+      assertEq(l2BlockNumber, 2, "Invalid block number");
+      assertEq(
+        startStateHash,
+        0xe3b20add23469bcbf25157ff75b81665564b089aa95083f8e095a3bb77062831,
+        "Invalid start state hash block 2"
+      );
+      assertEq(
+        endStateHash,
+        0xdc4f85374d479c6388a9bed0ddea9880422b515c88de0a76fd96b5c93c809b21,
+        "Invalid end state hash block 2"
+      );
+      assertEq(
+        publicInputsHash,
+        0x12e84ea31aa75fab86269181c8c09dbb8486e518e5db9ce4dad204068fc0a925,
+        "Invalid public input hash block 2"
+      );
+
+      rollup.process(bytes(""), block_2);
+
+      assertEq(rollup.rollupStateHash(), endStateHash, "Invalid rollup state hash");
+    }
   }
 }
diff --git a/yarn-project/acir-simulator/src/acvm/deserialize.ts b/yarn-project/acir-simulator/src/acvm/deserialize.ts
index db614d24236c..e1aa90e98bde 100644
--- a/yarn-project/acir-simulator/src/acvm/deserialize.ts
+++ b/yarn-project/acir-simulator/src/acvm/deserialize.ts
@@ -5,7 +5,7 @@ import {
   CallContext,
   ContractDeploymentData,
   EMITTED_EVENTS_LENGTH,
-  L1_MSG_STACK_LENGTH,
+  NEW_L2_TO_L1_MSGS_LENGTH,
   NEW_COMMITMENTS_LENGTH,
   NEW_NULLIFIERS_LENGTH,
   PrivateCircuitPublicInputs,
@@ -80,7 +80,7 @@ export function extractPublicInputs(partialWitness: ACVMWitness, acir: Buffer):
   const newNullifiers = witnessReader.readFieldArray(NEW_NULLIFIERS_LENGTH);
   const privateCallStack = witnessReader.readFieldArray(PRIVATE_CALL_STACK_LENGTH);
   const publicCallStack = witnessReader.readFieldArray(PUBLIC_CALL_STACK_LENGTH);
-  const l1MsgStack = witnessReader.readFieldArray(L1_MSG_STACK_LENGTH);
+  const newL2ToL1Msgs = witnessReader.readFieldArray(NEW_L2_TO_L1_MSGS_LENGTH);
 
   const privateDataTreeRoot = witnessReader.readField();
   const nullifierTreeRoot = witnessReader.readField();
@@ -102,7 +102,7 @@ export function extractPublicInputs(partialWitness: ACVMWitness, acir: Buffer):
     newNullifiers,
     privateCallStack,
     publicCallStack,
-    l1MsgStack,
+    newL2ToL1Msgs,
     privateDataTreeRoot,
     nullifierTreeRoot,
     contractTreeRoot,
diff --git a/yarn-project/acir-simulator/src/acvm/serialize.ts b/yarn-project/acir-simulator/src/acvm/serialize.ts
index 5b2b13958a12..7505f753851a 100644
--- a/yarn-project/acir-simulator/src/acvm/serialize.ts
+++ b/yarn-project/acir-simulator/src/acvm/serialize.ts
@@ -51,7 +51,7 @@ export function toACVMPublicInputs(publicInputs: PrivateCircuitPublicInputs): AC
     ...publicInputs.newNullifiers.map(toACVMField),
     ...publicInputs.privateCallStack.map(toACVMField),
     ...publicInputs.publicCallStack.map(toACVMField),
-    ...publicInputs.l1MsgStack.map(toACVMField),
+    ...publicInputs.newL2ToL1Msgs.map(toACVMField),
 
     toACVMField(publicInputs.historicPrivateDataTreeRoot),
     toACVMField(publicInputs.historicPrivateNullifierTreeRoot),
diff --git a/yarn-project/circuits.js/src/structs/__snapshots__/private_circuit_public_inputs.test.ts.snap b/yarn-project/circuits.js/src/structs/__snapshots__/private_circuit_public_inputs.test.ts.snap
index 7b79b0716a92..933310b2f98f 100644
--- a/yarn-project/circuits.js/src/structs/__snapshots__/private_circuit_public_inputs.test.ts.snap
+++ b/yarn-project/circuits.js/src/structs/__snapshots__/private_circuit_public_inputs.test.ts.snap
@@ -15,7 +15,7 @@ new_commitments: [ 0x400 0x401 0x402 0x403 ]
 new_nullifiers: [ 0x500 0x501 0x502 0x503 ]
 private_call_stack: [ 0x600 0x601 0x602 0x603 ]
 public_call_stack: [ 0x700 0x701 0x702 0x703 ]
-l1_msg_stack: [ 0x800 0x801 ]
+new_l2_to_l1_msgs: [ 0x800 0x801 ]
 historic_private_data_tree_root: 0x1000
 historic_nullifier_tree_root: 0x1100
 contract_deployment_data: constructor_vk_hash: 0x1
diff --git a/yarn-project/circuits.js/src/structs/constants.ts b/yarn-project/circuits.js/src/structs/constants.ts
index be28df64a271..5e247345c57d 100644
--- a/yarn-project/circuits.js/src/structs/constants.ts
+++ b/yarn-project/circuits.js/src/structs/constants.ts
@@ -7,20 +7,20 @@ export const EMITTED_EVENTS_LENGTH = 4;
 
 export const NEW_COMMITMENTS_LENGTH = 4;
 export const NEW_NULLIFIERS_LENGTH = 4;
+export const NEW_L2_TO_L1_MSGS_LENGTH = 2;
 
 export const STATE_TRANSITIONS_LENGTH = 4;
 export const STATE_READS_LENGTH = 4;
 
 export const PRIVATE_CALL_STACK_LENGTH = 4;
 export const PUBLIC_CALL_STACK_LENGTH = 4;
-export const L1_MSG_STACK_LENGTH = 2;
 
 export const KERNEL_NEW_COMMITMENTS_LENGTH = 4;
 export const KERNEL_NEW_NULLIFIERS_LENGTH = 4;
 export const KERNEL_NEW_CONTRACTS_LENGTH = 1;
 export const KERNEL_PRIVATE_CALL_STACK_LENGTH = 8;
 export const KERNEL_PUBLIC_CALL_STACK_LENGTH = 8;
-export const KERNEL_L1_MSG_STACK_LENGTH = 4;
+export const KERNEL_NEW_L2_TO_L1_MSGS_LENGTH = 2;
 export const KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH = 4;
 
 export const VK_TREE_HEIGHT = 3;
diff --git a/yarn-project/circuits.js/src/structs/kernel/__snapshots__/index.test.ts.snap b/yarn-project/circuits.js/src/structs/kernel/__snapshots__/index.test.ts.snap
index ddff9f823fa4..377f4b15cd90 100644
--- a/yarn-project/circuits.js/src/structs/kernel/__snapshots__/index.test.ts.snap
+++ b/yarn-project/circuits.js/src/structs/kernel/__snapshots__/index.test.ts.snap
@@ -24,8 +24,8 @@ private_call_stack:
 [ 0x301 0x302 0x303 0x304 0x305 0x306 0x307 0x308 ]
 public_call_stack:
 [ 0x401 0x402 0x403 0x404 0x405 0x406 0x407 0x408 ]
-l1_msg_stack:
-[ 0x501 0x502 0x503 0x504 ]
+new_l2_to_l1_msgs:
+[ 0x501 0x502 ]
 new_contracts:
 [ contract_address: 0x601
 portal_contract_address: 0x202020202020202020202020202020202020202
@@ -197,8 +197,8 @@ private_call_stack:
 [ 0x1301 0x1302 0x1303 0x1304 0x1305 0x1306 0x1307 0x1308 ]
 public_call_stack:
 [ 0x1401 0x1402 0x1403 0x1404 0x1405 0x1406 0x1407 0x1408 ]
-l1_msg_stack:
-[ 0x1501 0x1502 0x1503 0x1504 ]
+new_l2_to_l1_msgs:
+[ 0x1501 0x1502 ]
 new_contracts:
 [ contract_address: 0x1601
 portal_contract_address: 0x202020202020202020202020202020202020202
@@ -341,7 +341,7 @@ new_commitments: [ 0x2411 0x2412 0x2413 0x2414 ]
 new_nullifiers: [ 0x2511 0x2512 0x2513 0x2514 ]
 private_call_stack: [ 0x2611 0x2612 0x2613 0x2614 ]
 public_call_stack: [ 0x2711 0x2712 0x2713 0x2714 ]
-l1_msg_stack: [ 0x2811 0x2812 ]
+new_l2_to_l1_msgs: [ 0x2811 0x2812 ]
 historic_private_data_tree_root: 0x3011
 historic_nullifier_tree_root: 0x3111
 contract_deployment_data: constructor_vk_hash: 0x1
@@ -376,7 +376,7 @@ new_commitments: [ 0x2421 0x2422 0x2423 0x2424 ]
 new_nullifiers: [ 0x2521 0x2522 0x2523 0x2524 ]
 private_call_stack: [ 0x2621 0x2622 0x2623 0x2624 ]
 public_call_stack: [ 0x2721 0x2722 0x2723 0x2724 ]
-l1_msg_stack: [ 0x2821 0x2822 ]
+new_l2_to_l1_msgs: [ 0x2821 0x2822 ]
 historic_private_data_tree_root: 0x3021
 historic_nullifier_tree_root: 0x3121
 contract_deployment_data: constructor_vk_hash: 0x1
@@ -409,7 +409,7 @@ new_commitments: [ 0x2422 0x2423 0x2424 0x2425 ]
 new_nullifiers: [ 0x2522 0x2523 0x2524 0x2525 ]
 private_call_stack: [ 0x2622 0x2623 0x2624 0x2625 ]
 public_call_stack: [ 0x2722 0x2723 0x2724 0x2725 ]
-l1_msg_stack: [ 0x2822 0x2823 ]
+new_l2_to_l1_msgs: [ 0x2822 0x2823 ]
 historic_private_data_tree_root: 0x3022
 historic_nullifier_tree_root: 0x3122
 contract_deployment_data: constructor_vk_hash: 0x1
@@ -442,7 +442,7 @@ new_commitments: [ 0x2423 0x2424 0x2425 0x2426 ]
 new_nullifiers: [ 0x2523 0x2524 0x2525 0x2526 ]
 private_call_stack: [ 0x2623 0x2624 0x2625 0x2626 ]
 public_call_stack: [ 0x2723 0x2724 0x2725 0x2726 ]
-l1_msg_stack: [ 0x2823 0x2824 ]
+new_l2_to_l1_msgs: [ 0x2823 0x2824 ]
 historic_private_data_tree_root: 0x3023
 historic_nullifier_tree_root: 0x3123
 contract_deployment_data: constructor_vk_hash: 0x1
@@ -475,7 +475,7 @@ new_commitments: [ 0x2424 0x2425 0x2426 0x2427 ]
 new_nullifiers: [ 0x2524 0x2525 0x2526 0x2527 ]
 private_call_stack: [ 0x2624 0x2625 0x2626 0x2627 ]
 public_call_stack: [ 0x2724 0x2725 0x2726 0x2727 ]
-l1_msg_stack: [ 0x2824 0x2825 ]
+new_l2_to_l1_msgs: [ 0x2824 0x2825 ]
 historic_private_data_tree_root: 0x3024
 historic_nullifier_tree_root: 0x3124
 contract_deployment_data: constructor_vk_hash: 0x1
@@ -540,8 +540,8 @@ private_call_stack:
 [ 0x301 0x302 0x303 0x304 0x305 0x306 0x307 0x308 ]
 public_call_stack:
 [ 0x401 0x402 0x403 0x404 0x405 0x406 0x407 0x408 ]
-l1_msg_stack:
-[ 0x501 0x502 0x503 0x504 ]
+new_l2_to_l1_msgs:
+[ 0x501 0x502 ]
 new_contracts:
 [ contract_address: 0x601
 portal_contract_address: 0x202020202020202020202020202020202020202
@@ -676,8 +676,8 @@ private_call_stack:
 [ 0x301 0x302 0x303 0x304 0x305 0x306 0x307 0x308 ]
 public_call_stack:
 [ 0x401 0x402 0x403 0x404 0x405 0x406 0x407 0x408 ]
-l1_msg_stack:
-[ 0x501 0x502 0x503 0x504 ]
+new_l2_to_l1_msgs:
+[ 0x501 0x502 ]
 new_contracts:
 [ contract_address: 0x601
 portal_contract_address: 0x202020202020202020202020202020202020202
@@ -839,7 +839,7 @@ current_value: 0x1514
 current_value: 0x1515
  ]
 public_call_stack: [ 0x1611 0x1612 0x1613 0x1614 ]
-l1_msg_stack: [ 0x1711 0x1712 ]
+new_l2_to_l1_msgs: [ 0x1711 0x1712 ]
 historic_public_data_tree_root: 0x1811
 prover_address: 0x1812
 
@@ -883,7 +883,7 @@ current_value: 0x1814
 current_value: 0x1815
  ]
 public_call_stack: [ 0x1911 0x1912 0x1913 0x1914 ]
-l1_msg_stack: [ 0x1a11 0x1a12 ]
+new_l2_to_l1_msgs: [ 0x1a11 0x1a12 ]
 historic_public_data_tree_root: 0x1b11
 prover_address: 0x1b12
 
@@ -925,7 +925,7 @@ current_value: 0x1815
 current_value: 0x1816
  ]
 public_call_stack: [ 0x1912 0x1913 0x1914 0x1915 ]
-l1_msg_stack: [ 0x1a12 0x1a13 ]
+new_l2_to_l1_msgs: [ 0x1a12 0x1a13 ]
 historic_public_data_tree_root: 0x1b12
 prover_address: 0x1b13
 
@@ -967,7 +967,7 @@ current_value: 0x1816
 current_value: 0x1817
  ]
 public_call_stack: [ 0x1913 0x1914 0x1915 0x1916 ]
-l1_msg_stack: [ 0x1a13 0x1a14 ]
+new_l2_to_l1_msgs: [ 0x1a13 0x1a14 ]
 historic_public_data_tree_root: 0x1b13
 prover_address: 0x1b14
 
@@ -1009,7 +1009,7 @@ current_value: 0x1817
 current_value: 0x1818
  ]
 public_call_stack: [ 0x1914 0x1915 0x1916 0x1917 ]
-l1_msg_stack: [ 0x1a14 0x1a15 ]
+new_l2_to_l1_msgs: [ 0x1a14 0x1a15 ]
 historic_public_data_tree_root: 0x1b14
 prover_address: 0x1b15
 
@@ -1086,7 +1086,7 @@ current_value: 0x614
 current_value: 0x615
  ]
 public_call_stack: [ 0x711 0x712 0x713 0x714 ]
-l1_msg_stack: [ 0x811 0x812 ]
+new_l2_to_l1_msgs: [ 0x811 0x812 ]
 historic_public_data_tree_root: 0x911
 prover_address: 0x912
 
@@ -1130,7 +1130,7 @@ current_value: 0x914
 current_value: 0x915
  ]
 public_call_stack: [ 0xa11 0xa12 0xa13 0xa14 ]
-l1_msg_stack: [ 0xb11 0xb12 ]
+new_l2_to_l1_msgs: [ 0xb11 0xb12 ]
 historic_public_data_tree_root: 0xc11
 prover_address: 0xc12
 
@@ -1172,7 +1172,7 @@ current_value: 0x915
 current_value: 0x916
  ]
 public_call_stack: [ 0xa12 0xa13 0xa14 0xa15 ]
-l1_msg_stack: [ 0xb12 0xb13 ]
+new_l2_to_l1_msgs: [ 0xb12 0xb13 ]
 historic_public_data_tree_root: 0xc12
 prover_address: 0xc13
 
@@ -1214,7 +1214,7 @@ current_value: 0x916
 current_value: 0x917
  ]
 public_call_stack: [ 0xa13 0xa14 0xa15 0xa16 ]
-l1_msg_stack: [ 0xb13 0xb14 ]
+new_l2_to_l1_msgs: [ 0xb13 0xb14 ]
 historic_public_data_tree_root: 0xc13
 prover_address: 0xc14
 
@@ -1256,7 +1256,7 @@ current_value: 0x917
 current_value: 0x918
  ]
 public_call_stack: [ 0xa14 0xa15 0xa16 0xa17 ]
-l1_msg_stack: [ 0xb14 0xb15 ]
+new_l2_to_l1_msgs: [ 0xb14 0xb15 ]
 historic_public_data_tree_root: 0xc14
 prover_address: 0xc15
 
diff --git a/yarn-project/circuits.js/src/structs/kernel/combined_accumulated_data.ts b/yarn-project/circuits.js/src/structs/kernel/combined_accumulated_data.ts
index 34df6cb3ea1b..dc71598e333b 100644
--- a/yarn-project/circuits.js/src/structs/kernel/combined_accumulated_data.ts
+++ b/yarn-project/circuits.js/src/structs/kernel/combined_accumulated_data.ts
@@ -5,7 +5,7 @@ import { serializeToBuffer } from '../../utils/serialize.js';
 import { AggregationObject } from '../aggregation_object.js';
 import {
   EMITTED_EVENTS_LENGTH,
-  KERNEL_L1_MSG_STACK_LENGTH,
+  KERNEL_NEW_L2_TO_L1_MSGS_LENGTH,
   KERNEL_NEW_COMMITMENTS_LENGTH,
   KERNEL_NEW_CONTRACTS_LENGTH,
   KERNEL_NEW_NULLIFIERS_LENGTH,
@@ -167,7 +167,7 @@ export class CombinedAccumulatedData {
 
     public privateCallStack: Fr[],
     public publicCallStack: Fr[],
-    public l1MsgStack: Fr[],
+    public newL2ToL1Msgs: Fr[],
 
     public newContracts: NewContractData[],
 
@@ -180,7 +180,7 @@ export class CombinedAccumulatedData {
     assertLength(this, 'newNullifiers', KERNEL_NEW_NULLIFIERS_LENGTH);
     assertLength(this, 'privateCallStack', KERNEL_PRIVATE_CALL_STACK_LENGTH);
     assertLength(this, 'publicCallStack', KERNEL_PUBLIC_CALL_STACK_LENGTH);
-    assertLength(this, 'l1MsgStack', KERNEL_L1_MSG_STACK_LENGTH);
+    assertLength(this, 'newL2ToL1Msgs', KERNEL_NEW_L2_TO_L1_MSGS_LENGTH);
     assertLength(this, 'newContracts', KERNEL_NEW_CONTRACTS_LENGTH);
     assertLength(this, 'optionallyRevealedData', KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH);
     assertLength(this, 'stateTransitions', STATE_TRANSITIONS_LENGTH);
@@ -196,7 +196,7 @@ export class CombinedAccumulatedData {
       this.newNullifiers,
       this.privateCallStack,
       this.publicCallStack,
-      this.l1MsgStack,
+      this.newL2ToL1Msgs,
       this.newContracts,
       this.optionallyRevealedData,
       this.stateTransitions,
@@ -218,7 +218,7 @@ export class CombinedAccumulatedData {
       reader.readArray(KERNEL_NEW_NULLIFIERS_LENGTH, Fr),
       reader.readArray(KERNEL_PRIVATE_CALL_STACK_LENGTH, Fr),
       reader.readArray(KERNEL_PUBLIC_CALL_STACK_LENGTH, Fr),
-      reader.readArray(KERNEL_L1_MSG_STACK_LENGTH, Fr),
+      reader.readArray(KERNEL_NEW_L2_TO_L1_MSGS_LENGTH, Fr),
       reader.readArray(KERNEL_NEW_CONTRACTS_LENGTH, NewContractData),
       reader.readArray(KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH, OptionallyRevealedData),
       reader.readArray(STATE_TRANSITIONS_LENGTH, PublicDataWrite),
@@ -235,7 +235,7 @@ export class CombinedAccumulatedData {
       times(KERNEL_NEW_NULLIFIERS_LENGTH, Fr.zero),
       times(KERNEL_PRIVATE_CALL_STACK_LENGTH, Fr.zero),
       times(KERNEL_PUBLIC_CALL_STACK_LENGTH, Fr.zero),
-      times(KERNEL_L1_MSG_STACK_LENGTH, Fr.zero),
+      times(KERNEL_NEW_L2_TO_L1_MSGS_LENGTH, Fr.zero),
       times(KERNEL_NEW_CONTRACTS_LENGTH, NewContractData.empty),
       times(KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH, OptionallyRevealedData.empty),
       times(STATE_TRANSITIONS_LENGTH, PublicDataWrite.empty),
diff --git a/yarn-project/circuits.js/src/structs/private_circuit_public_inputs.ts b/yarn-project/circuits.js/src/structs/private_circuit_public_inputs.ts
index a8acd64909fd..5d296db4419c 100644
--- a/yarn-project/circuits.js/src/structs/private_circuit_public_inputs.ts
+++ b/yarn-project/circuits.js/src/structs/private_circuit_public_inputs.ts
@@ -5,7 +5,7 @@ import { CallContext } from './call_context.js';
 import {
   ARGS_LENGTH,
   EMITTED_EVENTS_LENGTH,
-  L1_MSG_STACK_LENGTH,
+  NEW_L2_TO_L1_MSGS_LENGTH,
   NEW_COMMITMENTS_LENGTH,
   NEW_NULLIFIERS_LENGTH,
   PRIVATE_CALL_STACK_LENGTH,
@@ -29,7 +29,7 @@ export class PrivateCircuitPublicInputs {
     public newNullifiers: Fr[],
     public privateCallStack: Fr[],
     public publicCallStack: Fr[],
-    public l1MsgStack: Fr[],
+    public newL2ToL1Msgs: Fr[],
     public historicPrivateDataTreeRoot: Fr,
     public historicPrivateNullifierTreeRoot: Fr,
     public historicContractTreeRoot: Fr,
@@ -42,7 +42,7 @@ export class PrivateCircuitPublicInputs {
     assertLength(this, 'newNullifiers', NEW_NULLIFIERS_LENGTH);
     assertLength(this, 'privateCallStack', PRIVATE_CALL_STACK_LENGTH);
     assertLength(this, 'publicCallStack', PUBLIC_CALL_STACK_LENGTH);
-    assertLength(this, 'l1MsgStack', L1_MSG_STACK_LENGTH);
+    assertLength(this, 'newL2ToL1Msgs', NEW_L2_TO_L1_MSGS_LENGTH);
   }
   /**
    * Create PrivateCircuitPublicInputs from a fields dictionary.
@@ -67,7 +67,7 @@ export class PrivateCircuitPublicInputs {
       frArray(NEW_NULLIFIERS_LENGTH),
       frArray(PRIVATE_CALL_STACK_LENGTH),
       frArray(PUBLIC_CALL_STACK_LENGTH),
-      frArray(L1_MSG_STACK_LENGTH),
+      frArray(NEW_L2_TO_L1_MSGS_LENGTH),
       Fr.ZERO,
       Fr.ZERO,
       Fr.ZERO,
@@ -90,7 +90,7 @@ export class PrivateCircuitPublicInputs {
       fields.newNullifiers,
       fields.privateCallStack,
       fields.publicCallStack,
-      fields.l1MsgStack,
+      fields.newL2ToL1Msgs,
       fields.historicPrivateDataTreeRoot,
       fields.historicPrivateNullifierTreeRoot,
       fields.historicContractTreeRoot,
diff --git a/yarn-project/circuits.js/src/structs/public_circuit_public_inputs.ts b/yarn-project/circuits.js/src/structs/public_circuit_public_inputs.ts
index 46da4d2bd438..64893ffff197 100644
--- a/yarn-project/circuits.js/src/structs/public_circuit_public_inputs.ts
+++ b/yarn-project/circuits.js/src/structs/public_circuit_public_inputs.ts
@@ -5,7 +5,7 @@ import { CallContext } from './call_context.js';
 import {
   ARGS_LENGTH,
   EMITTED_EVENTS_LENGTH,
-  L1_MSG_STACK_LENGTH,
+  NEW_L2_TO_L1_MSGS_LENGTH,
   PUBLIC_CALL_STACK_LENGTH,
   RETURN_VALUES_LENGTH,
   STATE_READS_LENGTH,
@@ -73,7 +73,7 @@ export class PublicCircuitPublicInputs {
     public stateTransitions: StateTransition[],
     public stateReads: StateRead[],
     public publicCallStack: Fr[],
-    public l1MsgStack: Fr[],
+    public newL2ToL1Msgs: Fr[],
     public historicPublicDataTreeRoot: Fr,
     public proverAddress: AztecAddress,
   ) {
@@ -81,7 +81,7 @@ export class PublicCircuitPublicInputs {
     assertLength(this, 'returnValues', RETURN_VALUES_LENGTH);
     assertLength(this, 'emittedEvents', EMITTED_EVENTS_LENGTH);
     assertLength(this, 'publicCallStack', PUBLIC_CALL_STACK_LENGTH);
-    assertLength(this, 'l1MsgStack', L1_MSG_STACK_LENGTH);
+    assertLength(this, 'newL2ToL1Msgs', NEW_L2_TO_L1_MSGS_LENGTH);
     assertLength(this, 'stateTransitions', STATE_TRANSITIONS_LENGTH);
     assertLength(this, 'stateReads', STATE_READS_LENGTH);
   }
@@ -109,7 +109,7 @@ export class PublicCircuitPublicInputs {
       times(STATE_TRANSITIONS_LENGTH, StateTransition.empty),
       times(STATE_READS_LENGTH, StateRead.empty),
       frArray(PUBLIC_CALL_STACK_LENGTH),
-      frArray(L1_MSG_STACK_LENGTH),
+      frArray(NEW_L2_TO_L1_MSGS_LENGTH),
       Fr.ZERO,
       AztecAddress.ZERO,
     );
@@ -128,7 +128,7 @@ export class PublicCircuitPublicInputs {
       fields.stateTransitions,
       fields.stateReads,
       fields.publicCallStack,
-      fields.l1MsgStack,
+      fields.newL2ToL1Msgs,
       fields.historicPublicDataTreeRoot,
       fields.proverAddress,
     ] as const;
diff --git a/yarn-project/circuits.js/src/structs/rollup/__snapshots__/base_rollup.test.ts.snap b/yarn-project/circuits.js/src/structs/rollup/__snapshots__/base_rollup.test.ts.snap
index 1e76e911043d..c02edc5e1d13 100644
--- a/yarn-project/circuits.js/src/structs/rollup/__snapshots__/base_rollup.test.ts.snap
+++ b/yarn-project/circuits.js/src/structs/rollup/__snapshots__/base_rollup.test.ts.snap
@@ -25,8 +25,8 @@ private_call_stack:
 [ 0x400 0x401 0x402 0x403 0x404 0x405 0x406 0x407 ]
 public_call_stack:
 [ 0x500 0x501 0x502 0x503 0x504 0x505 0x506 0x507 ]
-l1_msg_stack:
-[ 0x600 0x601 0x602 0x603 ]
+new_l2_to_l1_msgs:
+[ 0x600 0x601 ]
 new_contracts:
 [ contract_address: 0x700
 portal_contract_address: 0x101010101010101010101010101010101010101
@@ -170,8 +170,8 @@ private_call_stack:
 [ 0x500 0x501 0x502 0x503 0x504 0x505 0x506 0x507 ]
 public_call_stack:
 [ 0x600 0x601 0x602 0x603 0x604 0x605 0x606 0x607 ]
-l1_msg_stack:
-[ 0x700 0x701 0x702 0x703 ]
+new_l2_to_l1_msgs:
+[ 0x700 0x701 ]
 new_contracts:
 [ contract_address: 0x800
 portal_contract_address: 0x101010101010101010101010101010101010101
diff --git a/yarn-project/circuits.js/src/tests/factories.ts b/yarn-project/circuits.js/src/tests/factories.ts
index 73231ffbc74f..e496bb428ffd 100644
--- a/yarn-project/circuits.js/src/tests/factories.ts
+++ b/yarn-project/circuits.js/src/tests/factories.ts
@@ -38,14 +38,14 @@ import {
   CONTRACT_TREE_ROOTS_TREE_HEIGHT,
   EMITTED_EVENTS_LENGTH,
   FUNCTION_TREE_HEIGHT,
-  KERNEL_L1_MSG_STACK_LENGTH,
+  KERNEL_NEW_L2_TO_L1_MSGS_LENGTH,
   KERNEL_NEW_COMMITMENTS_LENGTH,
   KERNEL_NEW_CONTRACTS_LENGTH,
   KERNEL_NEW_NULLIFIERS_LENGTH,
   KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH,
   KERNEL_PRIVATE_CALL_STACK_LENGTH,
   KERNEL_PUBLIC_CALL_STACK_LENGTH,
-  L1_MSG_STACK_LENGTH,
+  NEW_L2_TO_L1_MSGS_LENGTH,
   NEW_COMMITMENTS_LENGTH,
   NEW_NULLIFIERS_LENGTH,
   NULLIFIER_TREE_HEIGHT,
@@ -118,7 +118,7 @@ export function makeAccumulatedData(seed = 1): CombinedAccumulatedData {
     range(KERNEL_NEW_NULLIFIERS_LENGTH, seed + 0x200).map(fr),
     range(KERNEL_PRIVATE_CALL_STACK_LENGTH, seed + 0x300).map(fr),
     range(KERNEL_PUBLIC_CALL_STACK_LENGTH, seed + 0x400).map(fr),
-    range(KERNEL_L1_MSG_STACK_LENGTH, seed + 0x500).map(fr),
+    range(KERNEL_NEW_L2_TO_L1_MSGS_LENGTH, seed + 0x500).map(fr),
     range(KERNEL_NEW_CONTRACTS_LENGTH, seed + 0x600).map(makeNewContractData),
     range(KERNEL_OPTIONALLY_REVEALED_DATA_LENGTH, seed + 0x700).map(makeOptionallyRevealedData),
     range(STATE_TRANSITIONS_LENGTH, seed + 0x800).map(makePublicDataWrite),
@@ -174,7 +174,7 @@ export function makePublicCircuitPublicInputs(seed = 0): PublicCircuitPublicInpu
     range(STATE_TRANSITIONS_LENGTH, seed + 0x400).map(makeStateTransition),
     range(STATE_READS_LENGTH, seed + 0x500).map(makeStateRead),
     frArray(PUBLIC_CALL_STACK_LENGTH, seed + 0x600),
-    frArray(L1_MSG_STACK_LENGTH, seed + 0x700),
+    frArray(NEW_L2_TO_L1_MSGS_LENGTH, seed + 0x700),
     fr(seed + 0x800),
     makeAztecAddress(seed + 0x801),
   );
@@ -316,7 +316,7 @@ export function makePrivateCircuitPublicInputs(seed = 0): PrivateCircuitPublicIn
     newNullifiers: range(NEW_NULLIFIERS_LENGTH, seed + 0x500).map(fr),
     privateCallStack: range(PRIVATE_CALL_STACK_LENGTH, seed + 0x600).map(fr),
     publicCallStack: range(PUBLIC_CALL_STACK_LENGTH, seed + 0x700).map(fr),
-    l1MsgStack: range(L1_MSG_STACK_LENGTH, seed + 0x800).map(fr),
+    newL2ToL1Msgs: range(NEW_L2_TO_L1_MSGS_LENGTH, seed + 0x800).map(fr),
     historicContractTreeRoot: fr(seed + 0x900), // TODO not in spec
     historicPrivateDataTreeRoot: fr(seed + 0x1000),
     historicPrivateNullifierTreeRoot: fr(seed + 0x1100), // TODO not in spec
diff --git a/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/abi.nr b/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/abi.nr
index 5b5ab2ad7e4f..52ed54067eda 100644
--- a/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/abi.nr
+++ b/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/abi.nr
@@ -73,7 +73,7 @@ struct PrivateCircuitPublicInputs {
     new_nullifiers: [Field; crate::abi::MAX_NEW_NULLIFIERS],
     private_call_stack: [Field; crate::abi::MAX_PRIVATE_CALL_STACK],
     public_call_stack: [Field; crate::abi::MAX_PUBLIC_CALL_STACK],
-    l1_msg_stack: [Field; crate::abi::MAX_L1_MSG_STACK],
+    new_l2_to_l1_msgs: [Field; crate::abi::MAX_L1_MSG_STACK],
     historic_private_data_tree_root: Field,
     historic_private_nullifier_tree_root: Field,
     historic_contract_tree_root: Field,
@@ -96,7 +96,7 @@ impl PrivateCircuitPublicInputs {
         fields = fields.push_array(self.new_nullifiers);
         fields = fields.push_array(self.private_call_stack);
         fields = fields.push_array(self.public_call_stack);
-        fields = fields.push_array(self.l1_msg_stack);
+        fields = fields.push_array(self.new_l2_to_l1_msgs);
         fields = fields.push(self.historic_private_data_tree_root);
         fields = fields.push(self.historic_private_nullifier_tree_root);
         fields = fields.push(self.historic_contract_tree_root);
@@ -172,7 +172,7 @@ impl Outputs {
             new_nullifiers: self.new_nullifiers.storage,
             private_call_stack: self.private_call_stack.storage,
             public_call_stack: self.public_call_stack.storage,
-            l1_msg_stack: self.l1_message_stack.storage,
+            new_l2_to_l1_msgs: self.l1_message_stack.storage,
             historic_private_data_tree_root: inputs.old_private_data_tree_root,
             historic_private_nullifier_tree_root: inputs.old_nullifier_tree_root,
             historic_contract_tree_root: inputs.old_contract_tree_root,
diff --git a/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/private_call_stack_item.nr b/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/private_call_stack_item.nr
index 4df7d3c989e3..162656317d78 100644
--- a/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/private_call_stack_item.nr
+++ b/yarn-project/noir-contracts/src/contracts/noir-aztec3/src/private_call_stack_item.nr
@@ -108,7 +108,7 @@ impl PrivateCallStackItem {
                 new_nullifiers: arr_copy_slice(fields, [0; crate::abi::MAX_NEW_NULLIFIERS], 30),
                 private_call_stack: arr_copy_slice(fields, [0; crate::abi::MAX_PRIVATE_CALL_STACK], 34),
                 public_call_stack: arr_copy_slice(fields, [0; crate::abi::MAX_PUBLIC_CALL_STACK], 38),
-                l1_msg_stack:arr_copy_slice(fields, [0; crate::abi::MAX_L1_MSG_STACK], 42),
+                new_l2_to_l1_msgs:arr_copy_slice(fields, [0; crate::abi::MAX_L1_MSG_STACK], 42),
                 historic_private_data_tree_root: fields[44],
                 historic_private_nullifier_tree_root: fields[45],
                 historic_contract_tree_root: fields[46],
diff --git a/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.test.ts b/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.test.ts
index f55806304c88..805f28d01fa3 100644
--- a/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.test.ts
+++ b/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.test.ts
@@ -4,6 +4,7 @@ import {
   BaseRollupInputs,
   CircuitsWasm,
   Fr,
+  NewContractData,
   PublicDataRead,
   PublicDataWrite,
   RootRollupPublicInputs,
@@ -18,8 +19,8 @@ import {
   makeProof,
   makeRootRollupPublicInputs,
 } from '@aztec/circuits.js/factories';
-import { toBufferBE } from '@aztec/foundation';
-import { Tx } from '@aztec/types';
+import { AztecAddress, EthAddress, toBufferBE } from '@aztec/foundation';
+import { ContractData, Tx } from '@aztec/types';
 import { MerkleTreeId, MerkleTreeOperations, MerkleTrees } from '@aztec/world-state';
 import { MockProxy, mock } from 'jest-mock-extended';
 import { default as levelup } from 'levelup';
@@ -34,6 +35,7 @@ import { ProcessedTx, makeEmptyProcessedTx, makeProcessedTx } from '../sequencer
 import { RollupSimulator } from '../simulator/index.js';
 import { WasmRollupCircuitSimulator } from '../simulator/rollup.js';
 import { CircuitBlockBuilder } from './circuit_block_builder.js';
+import { makePrivateTx } from '../index.js';
 
 export const createMemDown = () => (memdown as any)() as MemDown<any, any>;
 
@@ -302,6 +304,118 @@ describe('sequencer/circuit_block_builder', () => {
       const [l2Block] = await builder.buildL2Block(blockNumber, txs);
       expect(l2Block.number).toEqual(blockNumber);
     });
+
+    it('Build blocks on top of blocks l2 block with 4 txs', async () => {
+      const txs = [...(await Promise.all(times(4, makeEmptyProcessedTx)))];
+      const [block1] = await builder.buildL2Block(1, txs);
+      const [block2] = await builder.buildL2Block(2, txs);
+
+      expect(block1.number).toEqual(1);
+      expect(block2.number).toEqual(2);
+
+      /*const blocks = [block1, block2];
+      for (let i = 0; i < 2; i++) {
+        const block = blocks[i];
+        console.log(block.encode().toString('hex'));
+        console.log(`call data hash   : ${block.getCalldataHash().toString('hex')}`);
+        console.log(`start state hash: ${block.getStartStateHash().toString('hex')}`);
+        console.log(`end state hash  : ${block.getEndStateHash().toString('hex')}`);
+        console.log(`public input hash: ${block.getPublicInputsHash().toString()}`);
+      }*/
+    }, 10000);
+
+    it('Build blocks on top of blocks l2 block with 4 txs', async () => {
+      for (let i = 0; i < 2; i++) {
+        const tx = await makeProcessedTx(
+          Tx.createPrivate(makeKernelPublicInputs(1 + i), emptyProof, makeEmptyUnverifiedData()),
+        );
+        /*
+        const b = Buffer.alloc(20, 0);
+        b[19] = 2;
+        console.log(b);
+        tx.data.end.newContracts[0] = new NewContractData(
+          new AztecAddress(fr(1).toBuffer()),
+          new EthAddress(b),
+          fr(3),
+        );
+        console.log(tx.data.end.newContracts[0]);*/
+
+        const txsLeft = [tx, await makeEmptyProcessedTx()];
+        const txsRight = [await makeEmptyProcessedTx(), await makeEmptyProcessedTx()];
+
+        // Set tree roots to proper values in the tx
+        await setTxHistoricTreeRoots(tx);
+
+        // Calculate what would be the tree roots after the txs from the first base rollup land and update mock circuit output
+        await updateExpectedTreesFromTxs(txsLeft);
+        baseRollupOutputLeft.endContractTreeSnapshot = await getTreeSnapshot(MerkleTreeId.CONTRACT_TREE);
+        baseRollupOutputLeft.endNullifierTreeSnapshot = await getTreeSnapshot(MerkleTreeId.NULLIFIER_TREE);
+        baseRollupOutputLeft.endPrivateDataTreeSnapshot = await getTreeSnapshot(MerkleTreeId.PRIVATE_DATA_TREE);
+
+        // Same for the two txs on the right
+        await updateExpectedTreesFromTxs(txsRight);
+        baseRollupOutputRight.endContractTreeSnapshot = await getTreeSnapshot(MerkleTreeId.CONTRACT_TREE);
+        baseRollupOutputRight.endNullifierTreeSnapshot = await getTreeSnapshot(MerkleTreeId.NULLIFIER_TREE);
+        baseRollupOutputRight.endPrivateDataTreeSnapshot = await getTreeSnapshot(MerkleTreeId.PRIVATE_DATA_TREE);
+
+        // And update the root trees now to create proper output to the root rollup circuit
+        await updateRootTrees();
+        rootRollupOutput.endContractTreeSnapshot = await getTreeSnapshot(MerkleTreeId.CONTRACT_TREE);
+        rootRollupOutput.endNullifierTreeSnapshot = await getTreeSnapshot(MerkleTreeId.NULLIFIER_TREE);
+        rootRollupOutput.endPrivateDataTreeSnapshot = await getTreeSnapshot(MerkleTreeId.PRIVATE_DATA_TREE);
+        rootRollupOutput.endTreeOfHistoricContractTreeRootsSnapshot = await getTreeSnapshot(
+          MerkleTreeId.CONTRACT_TREE_ROOTS_TREE,
+        );
+        rootRollupOutput.endTreeOfHistoricPrivateDataTreeRootsSnapshot = await getTreeSnapshot(
+          MerkleTreeId.PRIVATE_DATA_TREE_ROOTS_TREE,
+        );
+
+        // Actually build a block!
+        const txs = [tx, await makeEmptyProcessedTx(), await makeEmptyProcessedTx(), await makeEmptyProcessedTx()];
+        const [block] = await builder.buildL2Block(1 + i, txs);
+
+        console.log(block);
+
+        // These output values are the same as in Decoder.t.sol tests
+        if (i === 0) {
+          expect(block.number).toEqual(1);
+          expect(block.getCalldataHash()).toEqual(
+            Buffer.from('9f1a00d7220a2b51a9c2591c2f85e089f03d06b01138586ea5e3656435d5e749', 'hex'),
+          );
+          expect(block.getStartStateHash()).toEqual(
+            Buffer.from('d3f7645c4b49d31bca62aca09aa26740d7e47d264f3021e2de2db40562944745', 'hex'),
+          );
+          expect(block.getEndStateHash()).toEqual(
+            Buffer.from('e3b20add23469bcbf25157ff75b81665564b089aa95083f8e095a3bb77062831', 'hex'),
+          );
+          expect(block.getPublicInputsHash().toBuffer()).toEqual(
+            Buffer.from('20638cd5e03d287dbd356af6e16fd852337f535b12d06f7266599c035696098d', 'hex'),
+          );
+        } else {
+          expect(block.number).toEqual(2);
+          expect(block.getCalldataHash()).toEqual(
+            Buffer.from('50f2f2dc986fc4022b8fdde8f2d610c82ee36776b282ca3514c12726dd9081ef', 'hex'),
+          );
+          expect(block.getStartStateHash()).toEqual(
+            Buffer.from('e3b20add23469bcbf25157ff75b81665564b089aa95083f8e095a3bb77062831', 'hex'),
+          );
+          expect(block.getEndStateHash()).toEqual(
+            Buffer.from('dc4f85374d479c6388a9bed0ddea9880422b515c88de0a76fd96b5c93c809b21', 'hex'),
+          );
+          expect(block.getPublicInputsHash().toBuffer()).toEqual(
+            Buffer.from('12e84ea31aa75fab86269181c8c09dbb8486e518e5db9ce4dad204068fc0a925', 'hex'),
+          );
+        }
+
+        // Printer useful for checking that output match contracts.
+        /*console.log(block);
+        console.log(block.encode().toString('hex'));
+        console.log(`call data hash   : ${block.getCalldataHash().toString('hex')}`);
+        console.log(`start state hash: ${block.getStartStateHash().toString('hex')}`);
+        console.log(`end state hash  : ${block.getEndStateHash().toString('hex')}`);
+        console.log(`public input hash: ${block.getPublicInputsHash().toString()}`);*/
+      }
+    }, 20000);
   });
 });
 
diff --git a/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.ts b/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.ts
index 953bca2abb99..5adc26ce7e34 100644
--- a/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.ts
+++ b/yarn-project/sequencer-client/src/block_builder/circuit_block_builder.ts
@@ -114,6 +114,7 @@ export class CircuitBlockBuilder implements BlockBuilder {
     const wasm = await CircuitsWasm.get();
     const newNullifiers = flatMap(txs, tx => tx.data.end.newNullifiers);
     const newCommitments = flatMap(txs, tx => tx.data.end.newCommitments);
+    const newL2ToL1Msgs = flatMap(txs, tx => tx.data.end.newL2ToL1Msgs);
     const newContracts = flatMap(txs, tx => tx.data.end.newContracts).map(cd => computeContractLeaf(wasm, cd));
     const newContractData = flatMap(txs, tx => tx.data.end.newContracts).map(
       n => new ContractData(n.contractAddress, n.portalContractAddress),
@@ -133,6 +134,7 @@ export class CircuitBlockBuilder implements BlockBuilder {
       endTreeOfHistoricContractTreeRootsSnapshot,
       newCommitments,
       newNullifiers,
+      newL2ToL1Msgs,
       newContracts,
       newContractData,
     });
diff --git a/yarn-project/sequencer-client/src/block_builder/standalone_block_builder.ts b/yarn-project/sequencer-client/src/block_builder/standalone_block_builder.ts
index 39d805a764cb..1771c7852486 100644
--- a/yarn-project/sequencer-client/src/block_builder/standalone_block_builder.ts
+++ b/yarn-project/sequencer-client/src/block_builder/standalone_block_builder.ts
@@ -42,8 +42,14 @@ export class StandaloneBlockBuilder implements BlockBuilder {
       MerkleTreeId.CONTRACT_TREE_ROOTS_TREE,
     );
 
+    // Note: The L2 -> L1 don't have a tree, so we can do it in the same manner there.
+    const l2ToL1TreeLeaves: Fr[] = [];
+
     for (const tx of txs) {
       await this.updateTrees(tx);
+      tx.data.end.newL2ToL1Msgs.forEach(n => {
+        l2ToL1TreeLeaves.push(n);
+      });
     }
 
     await this.updateRootTrees();
@@ -72,6 +78,7 @@ export class StandaloneBlockBuilder implements BlockBuilder {
       endTreeOfHistoricContractTreeRootsSnapshot,
       newCommitments: this.dataTreeLeaves.map(b => Fr.fromBuffer(b)),
       newNullifiers: this.nullifierTreeLeaves.map(b => Fr.fromBuffer(b)),
+      newL2ToL1Msgs: l2ToL1TreeLeaves,
       newContracts: this.contractTreeLeaves.map(b => Fr.fromBuffer(b)),
       newContractData: txs.flatMap(tx => tx.data.end.newContracts.map(mapContractData)),
     });
diff --git a/yarn-project/sequencer-client/src/simulator/fake_public.ts b/yarn-project/sequencer-client/src/simulator/fake_public.ts
index 51b008fe009a..408ce4fa90db 100644
--- a/yarn-project/sequencer-client/src/simulator/fake_public.ts
+++ b/yarn-project/sequencer-client/src/simulator/fake_public.ts
@@ -25,7 +25,7 @@ export class FakePublicCircuitSimulator implements PublicCircuitSimulator {
       args: tx.args,
       callContext: execution.callContext,
       emittedEvents: [],
-      l1MsgStack: [],
+      newL2ToL1Msgs: [],
       proverAddress: AztecAddress.random(),
       publicCallStack: [],
       returnValues: result.returnValues,
diff --git a/yarn-project/types/src/contract_data.ts b/yarn-project/types/src/contract_data.ts
index d6485b844ff8..b3cf56a24842 100644
--- a/yarn-project/types/src/contract_data.ts
+++ b/yarn-project/types/src/contract_data.ts
@@ -96,8 +96,7 @@ export class ContractData {
   public toBuffer(): Buffer {
     return serializeToBuffer(
       this.contractAddress,
-      this.portalContractAddress.toBuffer(),
-      this.bytecode || Buffer.alloc(4, 0),
+      this.portalContractAddress.toBuffer()
     );
   }
 
@@ -110,8 +109,7 @@ export class ContractData {
     const reader = BufferReader.asReader(buffer);
     const aztecAddr = AztecAddress.fromBuffer(reader);
     const ethAddr = new EthAddress(reader.readBytes(EthAddress.SIZE_IN_BYTES));
-    const publicFns = reader.readVector(EncodedContractFunction);
-    return new ContractData(aztecAddr, ethAddr, publicFns);
+    return new ContractData(aztecAddr, ethAddr);
   }
 
   /**
diff --git a/yarn-project/types/src/l2_block.ts b/yarn-project/types/src/l2_block.ts
index ab8a3f0284f8..193b3377ee85 100644
--- a/yarn-project/types/src/l2_block.ts
+++ b/yarn-project/types/src/l2_block.ts
@@ -3,10 +3,11 @@ import {
   KERNEL_NEW_COMMITMENTS_LENGTH,
   KERNEL_NEW_CONTRACTS_LENGTH,
   KERNEL_NEW_NULLIFIERS_LENGTH,
+  KERNEL_NEW_L2_TO_L1_MSGS_LENGTH,
 } from '@aztec/circuits.js';
 import { makeAppendOnlyTreeSnapshot } from '@aztec/circuits.js/factories';
 import { BufferReader, serializeToBuffer } from '@aztec/circuits.js/utils';
-import { Fr } from '@aztec/foundation';
+import { Fr, sha256, toBigIntBE, toBufferBE } from '@aztec/foundation';
 import { ContractData } from './contract_data.js';
 import { L2Tx } from './l2_tx.js';
 
@@ -48,6 +49,7 @@ export class L2Block {
     public endTreeOfHistoricContractTreeRootsSnapshot: AppendOnlyTreeSnapshot,
     public newCommitments: Fr[],
     public newNullifiers: Fr[],
+    public newL2ToL1Msgs: Fr[],
     public newContracts: Fr[],
     public newContractData: ContractData[],
   ) {}
@@ -59,6 +61,9 @@ export class L2Block {
     const newCommitments = Array(KERNEL_NEW_COMMITMENTS_LENGTH * txsPerBlock)
       .fill(0)
       .map(() => Fr.random());
+    const newL2ToL1Msgs = Array(KERNEL_NEW_L2_TO_L1_MSGS_LENGTH * txsPerBlock)
+      .fill(0)
+      .map(() => Fr.random());
     const newContracts = Array(KERNEL_NEW_CONTRACTS_LENGTH * txsPerBlock)
       .fill(0)
       .map(() => Fr.random());
@@ -80,6 +85,7 @@ export class L2Block {
       makeAppendOnlyTreeSnapshot(1),
       newCommitments,
       newNullifiers,
+      newL2ToL1Msgs,
       newContracts,
       newContractsData,
     );
@@ -104,6 +110,7 @@ export class L2Block {
     endTreeOfHistoricContractTreeRootsSnapshot: AppendOnlyTreeSnapshot;
     newCommitments: Fr[];
     newNullifiers: Fr[];
+    newL2ToL1Msgs: Fr[];
     newContracts: Fr[];
     newContractData: ContractData[];
   }) {
@@ -121,6 +128,7 @@ export class L2Block {
       fields.endTreeOfHistoricContractTreeRootsSnapshot,
       fields.newCommitments,
       fields.newNullifiers,
+      fields.newL2ToL1Msgs,
       fields.newContracts,
       fields.newContractData,
     );
@@ -147,6 +155,8 @@ export class L2Block {
       this.newCommitments,
       this.newNullifiers.length,
       this.newNullifiers,
+      this.newL2ToL1Msgs.length,
+      this.newL2ToL1Msgs,
       this.newContracts.length,
       this.newContracts,
       this.newContractData,
@@ -181,6 +191,7 @@ export class L2Block {
     const endTreeOfHistoricContractTreeRootsSnapshot = reader.readObject(AppendOnlyTreeSnapshot);
     const newCommitments = reader.readVector(Fr);
     const newNullifiers = reader.readVector(Fr);
+    const newL2ToL1Msgs = reader.readVector(Fr);
     const newContracts = reader.readVector(Fr);
     const newContractData = reader.readArray(newContracts.length, ContractData);
 
@@ -198,11 +209,134 @@ export class L2Block {
       endTreeOfHistoricContractTreeRootsSnapshot,
       newCommitments,
       newNullifiers,
+      newL2ToL1Msgs,
       newContracts,
       newContractData,
     );
   }
 
+  /**
+   * Computes the public inputs hash for the L2 block.
+   * The same output as the hash of RootRollupPublicInputs
+   * @return The public input hash for the L2 block as a field element
+   */
+  getPublicInputsHash() {
+    const buf = serializeToBuffer(
+      this.startPrivateDataTreeSnapshot,
+      this.startNullifierTreeSnapshot,
+      this.startContractTreeSnapshot,
+      this.startTreeOfHistoricPrivateDataTreeRootsSnapshot,
+      this.startTreeOfHistoricContractTreeRootsSnapshot,
+      this.endPrivateDataTreeSnapshot,
+      this.endNullifierTreeSnapshot,
+      this.endContractTreeSnapshot,
+      this.endTreeOfHistoricPrivateDataTreeRootsSnapshot,
+      this.endTreeOfHistoricContractTreeRootsSnapshot,
+      this.getCalldataHash(),
+    );
+    const temp = toBigIntBE(sha256(buf));
+    const p = BigInt('21888242871839275222246405745257275088548364400416034343698204186575808495617');
+    return Fr.fromBuffer(toBufferBE(temp % p, 32));
+  }
+
+  /**
+   * Computes the start state hash (should equal contract data before block)
+   * @returns The start state hash for the L2 block
+   */
+  getStartStateHash() {
+    const inputValue = serializeToBuffer(
+      this.number - 1,
+      this.startPrivateDataTreeSnapshot,
+      this.startNullifierTreeSnapshot,
+      this.startContractTreeSnapshot,
+      this.startTreeOfHistoricPrivateDataTreeRootsSnapshot,
+      this.startTreeOfHistoricContractTreeRootsSnapshot,
+    );
+    return sha256(inputValue);
+  }
+
+  /**
+   * Computes the end state hash (should equal contract data after block)
+   * @returns The end state hash for the L2 block
+   */
+  getEndStateHash() {
+    const inputValue = serializeToBuffer(
+      this.number,
+      this.endPrivateDataTreeSnapshot,
+      this.endNullifierTreeSnapshot,
+      this.endContractTreeSnapshot,
+      this.endTreeOfHistoricPrivateDataTreeRootsSnapshot,
+      this.endTreeOfHistoricContractTreeRootsSnapshot,
+    );
+    return sha256(inputValue);
+  }
+
+  /**
+   * Computes the calldata hash for the L2 block
+   * This calldata hash is also computed by the rollup contract when the block is submitted,
+   * and inside the circuit, it is part of the public inputs.
+   * @returns The calldata hash.
+   */
+  getCalldataHash() {
+    const computeRoot = (leafs: Buffer[]): Buffer => {
+      const layers: Buffer[][] = [leafs];
+      let activeLayer = 0;
+
+      while (layers[activeLayer].length > 1) {
+        const layer: Buffer[] = [];
+        const layerLength = layers[activeLayer].length;
+
+        for (let i = 0; i < layerLength; i += 2) {
+          const left = layers[activeLayer][i];
+          const right = layers[activeLayer][i + 1];
+
+          layer.push(sha256(Buffer.concat([left, right])));
+        }
+
+        layers.push(layer);
+        activeLayer++;
+      }
+
+      return layers[layers.length - 1][0];
+    };
+
+    const leafCount = this.newCommitments.length / (KERNEL_NEW_COMMITMENTS_LENGTH * 2);
+    const leafs: Buffer[] = [];
+
+    for (let i = 0; i < leafCount; i++) {
+      const inputValue = Buffer.concat([
+        this.newNullifiers[i * 8].toBuffer(),
+        this.newNullifiers[i * 8 + 1].toBuffer(),
+        this.newNullifiers[i * 8 + 2].toBuffer(),
+        this.newNullifiers[i * 8 + 3].toBuffer(),
+        this.newNullifiers[i * 8 + 4].toBuffer(),
+        this.newNullifiers[i * 8 + 5].toBuffer(),
+        this.newNullifiers[i * 8 + 6].toBuffer(),
+        this.newNullifiers[i * 8 + 7].toBuffer(),
+        this.newCommitments[i * 8].toBuffer(),
+        this.newCommitments[i * 8 + 1].toBuffer(),
+        this.newCommitments[i * 8 + 2].toBuffer(),
+        this.newCommitments[i * 8 + 3].toBuffer(),
+        this.newCommitments[i * 8 + 4].toBuffer(),
+        this.newCommitments[i * 8 + 5].toBuffer(),
+        this.newCommitments[i * 8 + 6].toBuffer(),
+        this.newCommitments[i * 8 + 7].toBuffer(),
+        this.newL2ToL1Msgs[i * 4].toBuffer(),
+        this.newL2ToL1Msgs[i * 4 + 1].toBuffer(),
+        this.newL2ToL1Msgs[i * 4 + 2].toBuffer(),
+        this.newL2ToL1Msgs[i * 4 + 3].toBuffer(),
+        this.newContracts[i * 2].toBuffer(),
+        this.newContracts[i * 2 + 1].toBuffer(),
+        this.newContractData[i * 2].contractAddress.toBuffer(),
+        this.newContractData[i * 2].portalContractAddress.toBuffer32(),
+        this.newContractData[i * 2 + 1].contractAddress.toBuffer(),
+        this.newContractData[i * 2 + 1].portalContractAddress.toBuffer32(),
+      ]);
+      leafs.push(sha256(inputValue));
+    }
+    return computeRoot(leafs);
+  }
+
   /**
    * Get the ith transaction in an L2 block.
    * @param txIndex - The index of the tx in the block.
@@ -222,6 +356,10 @@ export class L2Block {
       KERNEL_NEW_NULLIFIERS_LENGTH * txIndex,
       KERNEL_NEW_NULLIFIERS_LENGTH * (txIndex + 1),
     );
+    const newL2ToL1Msgs = this.newL2ToL1Msgs.slice(
+      KERNEL_NEW_L2_TO_L1_MSGS_LENGTH * txIndex,
+      KERNEL_NEW_L2_TO_L1_MSGS_LENGTH * (txIndex + 1),
+    );
     const newContracts = this.newContracts.slice(
       KERNEL_NEW_CONTRACTS_LENGTH * txIndex,
       KERNEL_NEW_CONTRACTS_LENGTH * (txIndex + 1),
@@ -230,7 +368,7 @@ export class L2Block {
       KERNEL_NEW_CONTRACTS_LENGTH * txIndex,
       KERNEL_NEW_CONTRACTS_LENGTH * (txIndex + 1),
     );
-    return new L2Tx(newCommitments, newNullifiers, newContracts, newContractData);
+    return new L2Tx(newCommitments, newNullifiers, newL2ToL1Msgs, newContracts, newContractData);
   }
 
   /**
@@ -278,6 +416,7 @@ export class L2Block {
       )}`,
       `newCommitments: ${inspectFrArray(this.newCommitments)}`,
       `newNullifiers: ${inspectFrArray(this.newNullifiers)}`,
+      `newL2ToL1Msgs: ${inspectFrArray(this.newL2ToL1Msgs)}`,
       `newContracts: ${inspectFrArray(this.newContracts)}`,
       `newContractData: ${inspectContractDataArray(this.newContractData)}`,
     ].join('\n');
diff --git a/yarn-project/types/src/l2_tx.ts b/yarn-project/types/src/l2_tx.ts
index fed27ef3cdd3..b891ef8f8b72 100644
--- a/yarn-project/types/src/l2_tx.ts
+++ b/yarn-project/types/src/l2_tx.ts
@@ -7,6 +7,7 @@ export class L2Tx {
   constructor(
     public newCommitments: Fr[],
     public newNullifiers: Fr[],
+    public newL2ToL1Msgs: Fr[],
     public newContracts: Fr[],
     public newContractData: ContractData[],
     private hash?: TxHash,
diff --git a/yarn-project/world-state/src/synchroniser/server_world_state_synchroniser.test.ts b/yarn-project/world-state/src/synchroniser/server_world_state_synchroniser.test.ts
index 882e0315add9..26db83dea118 100644
--- a/yarn-project/world-state/src/synchroniser/server_world_state_synchroniser.test.ts
+++ b/yarn-project/world-state/src/synchroniser/server_world_state_synchroniser.test.ts
@@ -48,6 +48,7 @@ const getMockBlock = (blockNumber: number, newContractsCommitments?: Buffer[]) =
     getMockTreeSnapshot(),
     [Fr.random()],
     [Fr.random()],
+    [Fr.random()],
     newContractsCommitments?.map(x => Fr.fromBuffer(x)) ?? [Fr.random()],
     [getMockContractData()],
   );