Ubuntu 12.04 won't load after update

My recently updated Ubuntu displays the following errors when I try to boot.

Firmware and/or mailbox pointer not initialized or corrupted, signature = 0xsomebs cmd = PING_FW
ERROR: Firmware size mismatch (have 16382, expected 376836)
cx23345_initialize_codec() f/w load failed.

I tried the boot-repair utility w/out any luck! I think it's the graphics driver. Anyone know how to reverse the drivers to the generic-default?