This bug or similar affects me. Installed from ubuntu-12.04-beta1-desktop-amd64.iso downloaded 3/3/2012.
Adding --no-log to grub : startup logs on screen to about point that " init: no available ptys " message looped and then hangs ( I presume the " no log" is effective, but not producing progress in startup.)
The /boot/grub/ directory has only a blacklist file, otherwise empty. Is this because it has not yet been set up for initrm?