diff --git a/.github/workflows/validate-config.yml b/.github/workflows/validate-config.yml
index 6c75f97..af71196 100644
--- a/.github/workflows/validate-config.yml
+++ b/.github/workflows/validate-config.yml
@@ -12,20 +12,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          ref: main
-
-      - name: Checkout main branch
-        run: |
-          echo "MAIN_SHA=$(git rev-parse HEAD)" >> $GITHUB_ENV
-
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Save HEAD commit SHA
-        run: |
-          echo "HEAD_SHA=$(git rev-parse HEAD)" >> $GITHUB_ENV
+        uses: actions/checkout@v2
 
       - name: Set up Node.js
         uses: actions/setup-node@v3
@@ -34,6 +21,12 @@ jobs:
 
       - name: Validate JSON files
         run: |
-          git diff --name-only $MAIN_SHA $HEAD_SHA | grep -q "^config.json$" && { echo "config.json must not be changed"; exit 1; } 
+          git fetch --all
+          export HEAD_SHA=$(git rev-parse HEAD)
+          export MAIN_SHA=$(git rev-parse origin/main)
+          echo $HEAD_SHA
+          echo $MAIN_SHA
+          echo $(git merge-base $MAIN_SHA $HEAD_SHA)
+          git diff --quiet $(git merge-base $MAIN_SHA $HEAD_SHA) $HEAD_SHA -- config.json || (echo "config.json must not be changed" && exit 1) 
           CHANGED_PROTOCOLS=$(git diff --name-only $MAIN_SHA $HEAD_SHA -- 'protocols/*' | grep '^protocols/' | xargs -L1 dirname | sed 's|protocols/||' | sort -u) 
           CHANGED_PROTOCOLS=$CHANGED_PROTOCOLS node validate-config.js
\ No newline at end of file