diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 64bd361e..3d25125f 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -53,12 +53,17 @@ jobs:
           echo "LIBJPEG_CFLAGS=$(pkg-config --cflags libturbojpeg)" >> $GITHUB_ENV
           echo "LIBJPEG_LIBS=$(pkg-config --libs libturbojpeg)" >> $GITHUB_ENV
 
+          wget https://github.com/fdopen/opam-repository-mingw/releases/download/0.0.0.2/opam64.tar.xz
+          tar -xf opam64.tar.xz
+          bash opam32/install.sh
+
       - uses: ocaml/setup-ocaml@v3
         with:
-          opam-repositories: "default:https://github.com/fdopen/opam-repository-mingw.git#opam2"
-          ocaml-compiler: "ocaml-variants.4.07.1+mingw64"
+          ocaml-compiler: "ocaml-variants.4.11.0+flambda+mingw64c"
           opam-disable-sandboxing: true
           dune-cache: true
+          opam-repositories: |
+            default: git+https://github.com/fdopen/opam-repository-mingw.git#opam2
 
       - name: Install deps & build
         run: opam install .  --with-test