diff --git a/.github/workflows/mirage.yml b/.github/workflows/mirage.yml
index 93e965116ff..1ede57b67b2 100644
--- a/.github/workflows/mirage.yml
+++ b/.github/workflows/mirage.yml
@@ -18,6 +18,7 @@ jobs:
       with:
         ocaml-compiler: 4.14.x
         opam-depext: false
+    - run: opam repo set-url default git+https://github.com/ocaml/opam-repository#dc24cade5f037058a4d86fcdd008159923152db5
     - run: sed -i s/1.3/2.7/ dune-project
     - run: opam pin add -n dune.dev git+https://github.com/ocaml/dune#$GITHUB_SHA
     - run: sudo apt install libseccomp-dev