diff --git a/.github/workflows/pr_diff.yaml b/.github/workflows/pr_diff.yaml
index aae7594..52f6a42 100644
--- a/.github/workflows/pr_diff.yaml
+++ b/.github/workflows/pr_diff.yaml
@@ -1,4 +1,5 @@
 name: PR Diff for Helm chart
+
 on:
   pull_request_target:
 
@@ -37,7 +38,7 @@ jobs:
             --set s3.bucket=abc
             --set s3.encrypt=abc
           )
-          helm template --debug ${OPTIONS[@]} --output-dir before ${{ github.server_url }}/${{ github.repository }}/archive/refs/heads/${{ github.base_ref }}.tar.gz
+          helm template --debug ${OPTIONS[@]} --output-dir before https://github.com/twuni/docker-registry.helm/archive/refs/heads/main.tar.gz
           helm template --debug ${OPTIONS[@]} --output-dir after .
           # https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#multiline-strings
           echo 'HELM_DIFF<<EOF' >> $GITHUB_ENV