diff --git a/build.sh b/build.sh
index 585e8e187..a65c6f05f 100755
--- a/build.sh
+++ b/build.sh
@@ -217,16 +217,16 @@ patch_osbuild() {
 }
 
 fixup_file_permissions() {
-    # Allow group write permissions on /usr/ because in upstream project's
-    # CI we want to overwrite software for testing. The directories
+    # Allow group write perms on directories under /usr/ because in upstream
+    # project's CI we want to overwrite software for testing. The directories
     # are typically owned by root:root and CI runs in openshift as a user
     # that is a member of the `root` (GID: 0) group.
     # See https://github.com/coreos/coreos-installer/pull/1716
-    chmod -R g+w /usr/
+    find /usr -type d -print0 | xargs -0 chmod -c g+w
     # And also one exception for /etc/grub.d (on arches that support
     # grub) since ostree upstream tries to put a symlink in this directory.
     if [ -d /etc/grub.d ]; then
-        chmod g+rwx /etc/grub.d
+        chmod -c g+rwx /etc/grub.d
     fi
 }