diff --git a/Dockerfile b/Dockerfile
index bbcc541..e2166de 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 FROM ocaml/opam:ubuntu-20.04-ocaml-4.14 AS opam
 RUN sudo cp /usr/bin/opam-2.1 /usr/local/bin/opam
-RUN sudo apt update && opam update && \
+RUN sudo apt update && ( cd opam-repository && git pull ) && opam update && \
     opam install 'mirage>4' && \
     eval $(opam env) && \
     git clone https://github.com/roburio/unipi.git && \