diff --git a/.github/workflows/prototyping.yml b/.github/workflows/prototyping.yml
index c68803c6..12f582db 100644
--- a/.github/workflows/prototyping.yml
+++ b/.github/workflows/prototyping.yml
@@ -29,7 +29,7 @@ jobs:
       run: sudo apt-get install -y cabal-install
     - name: cabal update
       working-directory: prototyping
-      run: cabal update
+      run: cabal update --index-state=${{ env.INDEX_STATE }}
     - name: cabal install
       working-directory: prototyping
       run: |