diff --git a/scripts/docker/Dockerfile.base b/scripts/docker/Dockerfile.base
index b8aff9ce1..1a43903b0 100644
--- a/scripts/docker/Dockerfile.base
+++ b/scripts/docker/Dockerfile.base
@@ -2,11 +2,11 @@
 
 FROM debian:stable
 
-MAINTAINER Pierre-Yves Strub <pierre-yves@strub.nu>
+LABEL org.opencontainers.image.maintainer="Pierre-Yves Strub <pierre-yves@strub.nu>"
 
 ARG user=charlie
 
-ENV DEBIAN_FRONTEND noninteractive
+ENV DEBIAN_FRONTEND=noninteractive
 
 RUN \
 	apt-get -q -y update && \
diff --git a/scripts/docker/Dockerfile.formosa b/scripts/docker/Dockerfile.formosa
new file mode 100644
index 000000000..8ff376734
--- /dev/null
+++ b/scripts/docker/Dockerfile.formosa
@@ -0,0 +1,7 @@
+# syntax = devthefuture/dockerfile-x
+
+FROM ./Dockerfile.build as build-formosa
+
+RUN \
+	opam install --deps-only --confirm-level=unsafe-yes jasmin && \
+	opam clean
diff --git a/scripts/docker/Dockerfile.test b/scripts/docker/Dockerfile.test
index f8dcd165d..2e9522d3a 100644
--- a/scripts/docker/Dockerfile.test
+++ b/scripts/docker/Dockerfile.test
@@ -5,7 +5,6 @@ FROM ./Dockerfile.build
 ARG EC_VERSION=main
 
 RUN \
-	opam pin --dev-repo \
-	add -n easycrypt https://github.com/EasyCrypt/easycrypt.git#${EC_VERSION} && \
+	opam pin add -n easycrypt https://github.com/EasyCrypt/easycrypt.git#${EC_VERSION} && \
 	opam install -v easycrypt && \
 	rm -rf .opam/packages.dev/*