I also tried this at the prompt:
linux /boot/vmlinuz-2.6.31-14-generic root=/dev/sda2 loop=/ubuntu/disks/root.disk ro initrd /boot/initrd.img-2.6.31-14-generic boot
...but there's no /dev/sda* (or /dev/hda*, for that matter)
I also tried this at the prompt:
linux /boot/vmlinuz- 2.6.31- 14-generic root=/dev/sda2 loop=/ubuntu/ disks/root. disk ro img-2.6. 31-14-generic
initrd /boot/initrd.
boot
...but there's no /dev/sda* (or /dev/hda*, for that matter)