重建 bootloader 選單

This is the correct way to install grub2 from a Linux LiveCD/USB:

sdXY is your / Linux partition (e.g. sda1)

sdX is the hard-disk containing the linux partition (e.g. sda)

mount /dev/sdXY /mnt

mount --bind /dev /mnt/dev

mount --bind /proc /mnt/proc

mount --bind /sys /mnt/sys

chroot /mnt

grub-install /dev/sdX

update-grub

exit # (Ctrl+D)

umount /mnt/dev

umount /mnt/proc

umount /mnt/sys

umount /mnt

reboot

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