diff --git a/scripts/docker/build-box/Dockerfile b/scripts/docker/build-box/Dockerfile
index 3681578294..eabe8d6b64 100644
--- a/scripts/docker/build-box/Dockerfile
+++ b/scripts/docker/build-box/Dockerfile
@@ -28,6 +28,7 @@ ENV OPAMJOBS    2
 RUN \
 	opam init -a && \
 	opam switch -v -A 4.03.0 easycrypt && \
+	eval `opam config env` && \
 	opam remote add easycrypt https://github.com/EasyCrypt/opam.git && \
 	opam install depext && opam depext easycrypt ec-provers && \
 	opam install ec-provers && \