ubuntu@ubuntu:~$ sudo -i
root@ubuntu:~# umount /dev/sda1 /dev/sda3
umount: /dev/sda1: not mounted
root@ubuntu:~# umount /dev/sda3
umount: /dev/sda3: not mounted
root@ubuntu:~# mount /dev/sda3 /mnt/gentoo
root@ubuntu:~# mount /dev/sda1 /mnt/gentoo/boot
root@ubuntu:~# mount -t proc none /mnt/gentoo/proc
root@ubuntu:~# mount -o bind /dev /mnt/gentoo/dev
root@ubuntu:~# chroot /mnt/gentoo /bin/bash
ubuntu / # env-update
>>> Regenerating /etc/ld.so.cache...
ubuntu / # source /etc/profile
ubuntu / # export PS1="(chroot) $PS1"
(chroot) ubuntu / #