diff --git a/.github/workflows/js_of_ocaml.yml b/.github/workflows/js_of_ocaml.yml
index bd4f22b0fe..395676097d 100644
--- a/.github/workflows/js_of_ocaml.yml
+++ b/.github/workflows/js_of_ocaml.yml
@@ -145,6 +145,9 @@ jobs:
         # It's faster to use a cached version
         run: opam install --fake binaryen-bin
 
+      - name: pin dune
+        run: opam pin add dune https://github.com/hhugo/dune.git#jsoo-shape2
+
       - run: opam install . --best-effort --solver builtin-mccs+glpk
         if: ${{ matrix.skip-test }}
 
diff --git a/.github/workflows/wasm_of_ocaml.yml b/.github/workflows/wasm_of_ocaml.yml
index 251ba04a6f..4f29334a79 100644
--- a/.github/workflows/wasm_of_ocaml.yml
+++ b/.github/workflows/wasm_of_ocaml.yml
@@ -107,6 +107,9 @@ jobs:
       - run: opam install conf-pkg-config conf-mingw-w64-gcc-i686 conf-mingw-w64-g++-x86_64
         if: runner.os == 'Windows'
 
+      - name: pin dune
+        run: opam pin add dune https://github.com/hhugo/dune.git#jsoo-shape2
+
       - name: Pin wasm_of_ocaml
         working-directory: ./wasm_of_ocaml
         run: opam pin . -n --with-version dev