On Nov 8, 2012, at 11:27 AM, Alex Kanavin <[email protected]> wrote: > 2012/11/8 Chris Murphy <[email protected]>: >> You are EFI booted. You might find out what created that inhospitable hybrid >> MBR. Oh I bet you prepared the drive using Boot Camp Assistant first, >> didn't you? If you did and don't also have Windows on the computer, you >> might use gdisk to create a new protective MBR, and write out a new GPT. >> The hybrid MBR is fraught with problems and technically right now you have a >> stale and invalid GPT. > > Er, no :) I never even ran boot camp assistant, I reduced the size of > OS X partition with Disk Utility, and then proceeded to Ubuntu > installation. That's when the hybrid MBR was created, probably.
If the Ubuntu installer was booted in EFI mode, and thus installed an EFI capable bootloader, it makes no sense it would created a hybrid MBR. If it did, it's a bug. I sooner expect that Disk Utility, which depends on diskutil resizevolume, probably made by default an MS-DOS (FAT32) volume from the newly freed up space from your resized JHFS+ volume. Whenever FAT32 is created by diskutil, a hybrid MBR is created. > I know > hybrid MBR is a hack made for one specific purpose of booting Windows, > but it doesn't seem to give me trouble, I'll probably just leave it > there. Fortunately both XNU and linux will defer to the GPT, but technically a hybrid MBR's mere existence is supposed to invalidate the GPT. Apple's own technote on this says that such a disk should be proscribed from further partition changes. Honestly, for EFI booting, GRUB2 is not a good option, I think it's overly complicated and you'd be better off using rEFInd (rEFIt is no longer maintained), and using the linux efistub as your bootloader. It's much more sane. Chris Murphy _______________________________________________ Help-grub mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-grub
