sudo mount /dev/hda1 /mnt/hda
sudo mount -t proc proc /mnt/hda/proc
sudo mount /dev/vg/h2g2 /mnt/hda/mnt/h2g2
sudo chroot /mnt/hda /bin/bash
env-update && source /etc/profile
emerge -uv world
exit
sudo umount /mnt/hda/mnt/h2g2
sudo umount /mnt/hda/proc <epcim@dontpanic:~
sudo umount /mnt/hda