ubuntu@ubuntu:~$ sudo mount /dev/sda6 /mnt
ubuntu@ubuntu:~$ sudo mount --bind /dev /mnt/dev
ubuntu@ubuntu:~$ sudo mount --bind /proc /mnt/proc
ubuntu@ubuntu:~$ sudo mount --bind /sys /mnt/sys
ubuntu@ubuntu:~$ sudo chroot /mnt
root@ubuntu:/# mount /dev/sda2 /boot
root@ubuntu:/# grub-install --target=x86_64-efi --efi-directory= /dev/sda2/boot --bootloader-id=grub
Installing for x86_64-efi platform.
grub-install: error: failed to get canonical path of `'.
root@ubuntu:/#