diff --git a/INSTALL/grub/grub.cfg b/INSTALL/grub/grub.cfg
index f75c9ca6..a466f9f3 100644
--- a/INSTALL/grub/grub.cfg
+++ b/INSTALL/grub/grub.cfg
@@ -1816,6 +1816,7 @@ export gfxpayload
 export vtoydev
 export vtoy_path
 export vtdebug_flag
+export vtoy_iso_fs
 export vtoy_iso_part
 export vtoy_efi_part
 export VENTOY_VERSION