ubuntu@ubuntu:~$ sudo mount /dev/mapper/ubuntu--vg-root /mnt
ubuntu@ubuntu:~$ sudo mount --bind /dev /mnt/dev
ubuntu@ubuntu:~$ ls /mnt/boot
efi
ubuntu@ubuntu:~$ sudo mount /dev/sda2 /mnt/boot
ubuntu@ubuntu:~$ sudo chroot /mnt

root@ubuntu:/# mount -t proc none /proc
root@ubuntu:/# mount -t sysfs none /sys
root@ubuntu:/# mount -t devpts none /dev/pts
root@ubuntu:/# export HOME=/root
root@ubuntu:/# export LC_ALL=C

root@ubuntu:/# apt-get update
root@ubuntu:/# apt-get -y install linux-image-generic

root@ubuntu:/# umount /proc || umount -lf /proc
root@ubuntu:/# umount /sys /dev/pts
root@ubuntu:/# exit
exit
ubuntu@ubuntu:~$ sudo umount /mnt/dev /mnt