I’m triple booting my iMac.
But after installing “GRUB/LILO”, I stilll need to insert the “DVD” to boot into either Win 7 or opensuse 11.3
Why is my install of the GRUB/LILO boot loader not working?
Error Message: No Bootable Device – Insert boot disk and press any key
I don’t know and I know nothing about iMacs, but did you install grub onto your disks master boot record (mbr) or a boot partition if they use these?
Maybe this link can help you.
GRUB Manual - Installation
Be very careful not to do anything to mess up your existing drive or installation.