diff --git a/iso/builder/build.sh b/iso/builder/build.sh
index 3ff3688..2b575e2 100755
--- a/iso/builder/build.sh
+++ b/iso/builder/build.sh
@@ -566,7 +566,7 @@ validate_iso_grub_theme_assets() {
     }
 
     iso_files="$(mktemp)"
-    list_iso_files "$iso_path" > "$iso_files" || {
+    iso_list_files "$iso_path" > "$iso_files" || {
         echo "ERROR: failed to list ISO files for GRUB theme validation" >&2
         rm -f "$iso_files"
         exit 1