diff --git a/debian.cfg b/debian.cfg
index c4e5c94..998b581 100644
--- a/debian.cfg
+++ b/debian.cfg
@@ -89,7 +89,6 @@ tasksel tasksel/first multiselect ssh-server
 d-i pkgsel/upgrade select none
 
 # B.4.11. 安装 bootloader
-d-i grub-installer/bootdev string default
 # 添加 bootx64.efi
 d-i grub2/force_efi_extra_removable boolean true
 
@@ -116,6 +115,7 @@ d-i partman/early_command string \
 
     xda=$(wget --tries=5 $confhome/get-xda.sh -O- | sh -s); \
     debconf-set partman-auto/disk "/dev/$xda"; \
+    debconf-set grub-installer/bootdev "/dev/$xda"; \
     rm -rf /usr/sbin/fdisk /usr/sbin/sfdisk; \
 
     ttys=$(wget --tries=5 $confhome/ttys.sh -O- | sh -s console=); \