diff --git a/preseed.cfg b/preseed.cfg
index b7b42cb..8c89b9d 100644
--- a/preseed.cfg
+++ b/preseed.cfg
@@ -49,6 +49,7 @@ d-i pkgsel/upgrade select none
 # B.4.11. 安装 bootloader
 d-i grub-installer/only_debian boolean true
 d-i grub-installer/with_other_os boolean false
+d-i grub-installer/bootdev string default
 d-i grub2/force_efi_extra_removable boolean true
 
 # B.4.12. 完成安装