I'm bitten by this bug as well. I notice that there are on tty1 error messages saying "INVALID X86 OPCODE". I'm on amd64.
My current workaround is to remove usplash -- no boot splash and very slow booting https://launchpad.net/bugs/61711 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
