Drive 1: 160GB, /home
Drive 2: 40GB, /boot and /

sudo mkdir /media/root
sudo mount /dev/sda1 /media/root
sudo mount /dev/sda2 /media/root/boot
sudo mount /dev/sda3 /media/root/home

sudo mount -B /proc /media/root/proc
sudo mount -B /dev /media/root/dev
sudo mount -B /sys /media/root/sys

sudo chroot /media/root
sudo update-grub