diff --git a/iso/builder/build.sh b/iso/builder/build.sh
index d70c5bb..0a87a43 100755
--- a/iso/builder/build.sh
+++ b/iso/builder/build.sh
@@ -28,6 +28,9 @@ done
 
 . "${BUILDER_DIR}/VERSIONS"
 export PATH="$PATH:/usr/local/go/bin"
+
+# Allow git to read the bind-mounted repo (different UID inside container).
+git config --global safe.directory "${REPO_ROOT}"
 mkdir -p "${DIST_DIR}"
 mkdir -p "${CACHE_ROOT}"
 : "${GOCACHE:=${CACHE_ROOT}/go-build}"