I'm dead in the water with my MacBook Pro 5,1 with the following message
error: unknown filesystem
grub rescue> _
(it is hung - I cannot type any commands here)
I kind of think its a partition problem, so I'm going to repartition using OSX's disc utility, reload OSX and then try f12
Sigh, I spent the whole night on this with no progress.
Another issue is the livecd failed to work, tried nomodeset and xdriver=vesa but these didn't work. The funny thing is that the dvd works - I booted up (with nomodeset & xdriver=vesa), and I was able to install f12.
btw, I had no problems with the RC of f12. I may go that route if this fails.