After boot password entry I can see the following on the screen:
mounting /dev on /root/dev failed: No such file or directory.
mounting /sys on /root/sys failed: No such file or directory.
mounting /proc on /root/proc failed: No such file or directory.
Target filesystem doesn't have /sbin/init.
No init found.
Try passing init=bootarg.
then the busybox stuff. (Ubuntu 1:1.13.3-1 ubuntu 11) built-in shell (ash).
I saw this problem asked and solved for someone in 2010 but the instructions there didn't work for me.