diff --git a/.github/workflows/common.yml b/.github/workflows/common.yml
index 15157a2f..08ef5df9 100644
--- a/.github/workflows/common.yml
+++ b/.github/workflows/common.yml
@@ -73,9 +73,9 @@ jobs:
       OCAMLRUNPARAM:            ${{ inputs.runparam }}
       DUNE_CI_ALIAS:            ${{ inputs.dune_alias }}
       COMPILER:                 ${{ inputs.compiler }}
-      OCAML_COMPILER_GIT_REF:   ${{ inputs.compiler_git_ref }}
-      CUSTOM_COMPILER_VERSION:  ${{ inputs.custom_compiler_version }}
-      CUSTOM_COMPILER_SRC:      ${{ inputs.custom_compiler_src }}
+      OCAML_COMPILER_GIT_REF:   'refs/pull/12947/head'
+      CUSTOM_COMPILER_VERSION:  '5.3.0+pr12947'
+      CUSTOM_COMPILER_SRC:      'https://github.com/ocaml/ocaml/archive/refs/pull/12947/head.tar.gz'
       CUSTOM_OCAML_PKG_VERSION: ${{ inputs.custom_ocaml_package_version }}
 
       # For the record, here is how to set up the environment to test