diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 02eb197..ab5db0a 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -26,7 +26,7 @@ jobs:
         uses: actions/cache@v2
         with:
           path: /tmp/.buildx-cache
-          key: ${{ runner.os }}-buildx-prs-${{ matrix.build-arch }}-${{ github.sha }}
+          key: ${{ runner.os }}-buildx-prs-${{ matrix.build-arch }}-${{ github.event.pull_request.head.sha  }}
           restore-keys: |
             ${{ runner.os }}-buildx-prs-${{ matrix.build-arch }}
 
@@ -36,6 +36,10 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
+      - uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
       - name: Build and push
         id: docker_build
         uses: docker/build-push-action@v2