I am having issues with either garbled graphics or a black screen following the install of 12.04 on my 2009 Mac Mini, connected to a Philips 42" LCD TV via HDMI.
During install I first encountered the garbled video, so I added nosplash, noquiet and nomodeset to the boot options, and this let me carry out the install without issues.
Upon reboot however I'm having the same problem, however the nosplash, noquiet and/or nomodeset options aren't working - they just result in a black screen.
I've tried placing them before/after the $vthandoff command (no present when booting off startup media) with no difference. I've even tried removing that command - again nothing.
Trying different options like nomodeset=0, nouveau.modeset=0, xforcevesa etc - nothing works!