# mount the btrfs root subvolume mount /dev/sda1 /mnt -o subvol=/ # (optional) set the default subvolume btrfs sub set @ /mnt mount /proc /mnt/proc --bind mount /dev /mnt/dev --bind mount /sys /mnt/sys --bind chroot /mnt grub-install /dev/sda update-grub /dev/sda # activate first partition fdisk -l /dev/sda