diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index d70ea1c..53577bb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,6 +25,8 @@ jobs:
       - name: lint
         run: |
           make gofmt
+          TOPDIR=$(git rev-parse --show-toplevel)
+          echo "TOPDIR=${TOPDIR}" >> $GITHUB_ENV
 
       - name: make
         run: |
@@ -72,6 +74,7 @@ jobs:
           build-args: |
             ZOT_VERSION=2.0.0-rc5
             ROOTFS_VERSION=v0.0.17.231018
+            TOPDIR=$TOPDIR
           url: docker://zothub.io/machine/bootstrap
           tags: ${{ github.event.release.tag_name }}
           username: ${{ secrets.ZOTHUB_USERNAME }}