Description of problem: I was able to boot and install the x86_64 dvd version on a 27 inch imac, but the resulting system will not boot. I tried both refit and holding alt during the boot. Both give a message about no operating system being present. Syncing mbr with refit didn't help. Reinstalling grub using the dvd rescue feature (while chrooted) fails with "The file /boot/grub/stage1 not read correctly" I tried both with a single / partition (ext4) and by adding a ext3 /boot.
*** This bug has been marked as a duplicate of bug 503149 ***