CSM-BIOS boot notes:
Apple hardware tested:
mbp41 = MacBookPro 4,1 (2008), Nvidia Geforce8600M GT.
mbp82 = MacBookPro 8,2 (2011), Intel HD Graphics 3000 and AMD Radeon HD 6750M.
All notes based on booting with the Apple-EFI option-key startup menu to choose how to
boot, not rEFIt.
1. After default install using any installation type, and reboot, neither model loads
GRUB2 (and thus does not boot) by default. Pre or post-install work is needed.
2. Both models CAN boot and startup Fedora to a GUI login with pre- or post-install work.
a. 'nogpt' kernel parameter for Fedora only installs produces a bootable system
without post-install work.
b. In dual-boot (Mac OS + Fedora) anaconda isn't creating a hybrid MBR post-install,
therefore Apple's EFI startup disk menu doesn't see the F16 installation. Further,
creating the hybrid MBR in advance is useless as parted wipes out the hybrid MBR in favor
of a protective MBR just prior to installation. (See 3 below for additional fallout of
c. Triple boot (Mac OS, Fedora, Windows) is possible, but there are more ways this
won't work, than will work. And more ways that will work, but aren't good
partition schemes (invitations for data loss) since there really isn't such a thing as
a safe hybrid MBR + GPT. I have found one or two that I think are about as
"safe" as they can get, and it means that the user needs to install Mac OS,
Windows, Fedora, in that order, but located on the disk in order: Mac OS, Fedora,
3. Anaconda + parted consistently remove pre-existing hybrid MBRs, replacing them with
protective MBRs. The hybrid MBR will exist in a case where Windows has already been
installed (using Apple's Bootcamp application). If removed in favor of a protective
MBR, Windows is no longer bootable. So not only is Fedora not bootable, a previously
bootable Windows is no longer bootable. This happens with either EFI or BIOS mode installs
So either anaconda needs to proceed no further upon discovery of a hybrid MBR, or it needs
to become pretty good at sorting out hybrid MBR and GPT schemes that are
4. gptsycnc: I don't think gptsync has such a sophisticated heuristic for creating
such hybrid MBRs - I regularly see it produce very linear MBRs while suggesting huge
percentages of the disk are empty. Any MBR only aware tool would see these areas as fair
game - what I call an invitation for data loss and probably not a good idea.
5. If all requirements are met, Apple's startup disk menu (option-key at startup
chime) will present a single "Windows" disk icon which if selected will load
GRUB2 and its menu. That "Windows" label is apparently hard coded in Apple's
EFI for any foreign OS requiring legacy CSM-BIOS booting.
Additional EFI boot notes:
1. By default EFI//EFI/redhat/grub.efi isn't found by Apple's EFI and install a
choosable option. If it and the .conf are moved to EFI//EFI/BOOT/BOOTX64.efi and .conf,
both models have an "EFI Boot" labeled disk icon in the option-key startup menu.
I'm guessing like the "Windows" equivalent, that "EFI Boot" is
This is being addressed by this:
2. GRUB-EFI (legacy) regularly just hangs are loading the kernel and initramfs, on mbp41.
I don't have this problem with GRUB2-EFI but I still have other problems mentioned in
the previous email.