Grub je zavaděč systému.

mkdir /mnt/root
mount /dev/fedora/root /mnt/root
mount /dev/sdXY /mnt/root/boot

mount -o bind /dev /mnt/root/dev
mount -o bind /proc /mnt/root/proc
mount -o bind /sys /mnt/root/sys
mount -t tmpfs /mnt/root/tmpfs /mnt/root/tmp

chroot /mnt/root
grub2-install /dev/sdX
grub2-mkconfig -o /boot/grub2/grub.cfg