grub2-bios in partition does not boot after upgrad

view full story

https://bbs.archlinux.org – I installed grub2-bios into partition ,instead of MBR.I removed /boot/grub directory before the upgrade just in case# chattr -i /boot/grub/core.img # rm -rf /boot/grub/ # pacman -Syu # modprobe dm-modAfter grub2-bios and grub2-common have been upgraded , I ran# grub-install --directory=/usr/lib/grub/i386-pc --target=i386-pc --boot-directory=/boot --recheck --force --debug /dev/sda1 # chattr +i /boot/grub/i386-pc/core.imgEdit /etc/default/grub , regenerate grub.cfg and reboot.Then grub returns onlyGRUB _I can do nothing other than rebooting by ctrl+alt+delete.There are neither 「welcome to GRU (HowTos)