Description of problem:
After a successful install on my 2011 iMac I cannot boot into F15. I use rEFIT to select which OS to boot. Neither 'Boot Legacy OS from HD' or EFI boot works. When I select EFI boot (EFI\redhat\grub.efi) I only get the grub prompt.

Version-Release number of selected component (if applicable):
grub-0.97-71

How reproducible:
always

Steps to Reproduce:
1. Install F15 from x86-64 DVD
2. Select /dev/sda3 to install bootloader
3.
  
Actual results:
Booting either boot option fails.

Expected results:
Happily booting into F15

Additional info:
F15 itself seems to work great on the 2011 iMac my 2nd monitor works out of the box!

checking grub.conf I see references to hd0,2 while the /boot partition is on /dev/sda3. /dev/sda2 is OSX. After modifying it I still do net get a grub menu.

When I use the 'find (hd0,3)/' command in the grub shell I get 'Error 18: Selected cylinder exceeds maximum supported by BIOS'

I can supply more info/test more if needed.