2011-12-24 23:08:41 UTC
I have found EFI booting Apple hardware is problematic on the two models I've tested. I think these are kernel related problems that would need to be sorted out to get a full boot and startup to a GUI login. CSM-BIOS boot works OK on these models.
Apple hardware tested:
mbp41 = MacBookPro 4,1 (2008), Nvidia Geforce8600M GT.
mbp82 = MacBookPro 8,2 (2011), Intel HD Graphics 3000 and AMD Radeon HD 6750M.
1. mbp41 booting is inconsistent. Without additional kernel parameters I generally end up with one of three results: successful boot to GUI login window; hang at nouveau (dmesg points to VBIOS corruption having occurred very early during boot); hang when unpacking initramfs (possibly the same intermittent corruption of VBIOS, causes corruption when unpacking initramfs).
With 'nomodeset' I usually am able to boot and complete startup except for x. So it's a text only situation. But all other function appears reliable.
2. mbp82 booting of kernel and initramfs appears to work 100% of the time. However immediately after a GRUB menu item is chosen, GRUB-EFI vanishes and is replaced with garbage on the screen. I speculate that in this boot mode, both video adapters are active at the same time and are conflicting maybe? In any event, I can't see anything. But it is possible to ssh into the computer or blindly type commands and they all appear to work.
Also, all EFI testing I've done is without rEFIt as I feel it adds another layer of unknowns to the process.