How can we make F17 be able to boot on Macs (with or without reFit)

[Adam Williamson]

On Fri, 2011-12-02 at 12:08 +0100, Andreas Tunek wrote:
> As you all might know, it is currently impossible to boot the default
> install of F16 on Macs. It does not seem to matter if you use boot
> loaders such as reFit and Bootcamp or remove MacOS completely and try
> to boot. Apparently, if you somehow (how to use it is not very clear
> from the "Common F16 bugs" page,
> http://fedoraproject.org/wiki/Common_F16_bugs#Incorrect_partition_type_assigned_to_.2Fboot_partition_on_GPT-labelled_disks)
> use the nogpt kernel parameter you might be able to install F16.
> 
> There are a couple of bugs open regarding this,
> https://bugzilla.redhat.com/show_bug.cgi?id=752548 and
> https://bugzilla.redhat.com/show_bug.cgi?id=746895 are two examples.
> 
> It seems like the boot procedure has changed quite a bit from F15 to
> F16, and not just the GRUB2 change. I am sure these were changed for
> the best of reasons, but it is very frustrating to not be able to use
> F16 on hardware that could run previous Fedoras very well. Also, there
> are a lot of Macs out in the wild, and by excluding them we shut out a
> large amount of (possible users).
> 
> So what could be done about this? Would it be enough to have a visible
> nopgt option in Anaconda? Should we do special "Boot test days"? Or is
> something else needed?

So, revisiting this: right now it seems like the aim for F17 is to focus
on native EFI boot and install on Mac, not installation using BIOS
compatibility mode. We should aim to fix any remaining issues with
booting Macs via EFI and test throughout F17 cycle to ensure it works.

In the past we have not supported EFI boot on Macs because the Apple
implementation of EFI is rather non-standard, but apparently just trying
to work with Apple's EFI quirks is our best shot at getting reliable
installs on Macs in future.

That's as I understand it from this morning's #anaconda discussion,
anyway.

As far as F16 goes, my current understanding is that it is possible to
install F16 onto some Macs via native EFI boot; however, we do have
problems booting some other Macs natively via EFI with F16. If you try
to do an F16 install in BIOS compatibility mode it may work and may not,
much like previous releases, but if you do it in such a way that Fedora
gets to format an entire disk, it will write a GPT disk label and that
certainly won't work for BIOS compatibility booting. I'm honestly not
sure of all the implications of the 'hybrid GPT' approach Macs can use
for dual-booting OS X (via EFI) and Windows (via BIOS compatibility)
with all this, I think that's where a lot of the complexity we see in
real-world Mac install cases comes in; one of the advantages of making
EFI our 'officially supported' way to install on Macs in future is we
don't have to worry about that, I guess.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
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