Re: EFI boot problem with MBP 5,4

[Daire Byrne]

Robert,

On Tue, Jan 5, 2010 at 5:15 PM, Daire Byrne <address@hidden> wrote:
>> It looks like recent kernels (namely 2.6.31 and 2.6.32) can't find the
>> initrd when booting from grub (efi) on a macbook pro 5,4 giving the
>> error:
>>
>>  RAMDISK: Couldn't find valid RAM disk image starting at 0.
>>
>> The 2.6.30 kernel does not seem to suffer from this so something must
>> have changed in 2.6.31+. I also tested all three kernels on a MBP4,1
>> and they all boot fine from grub - they find and load the initrd. In all
>> cases the grub.cfg and initrd remained the same and only the kernel
>> was changed. This could be a kernel issue but the fact that they all
>> boot on a MBP4,1 makes me think it is a EFI1.1 vs EFI 2.0 thing.
>>
>> As an aside I can get the nvidia module working with MBP5,4+2.6.30 but
>> a MBP4,1+2.6.30 can't find the vbios. Is this a known thing and is
>> there a possible fix for it?
>>
>
>Perhaps you could run a regression test (aka bisect) on Linux source?  This
>would help us figure out the problem (whether it's a bug in Linux, in GRUB
>or in your firmware).

I haven't yet had time to dig into this deeper and do the required
bisect work yet but when searching for similar reports I did find a
report about elilo not being able to boot since kernel 2.6.30.

  http://bugzilla.kernel.org/show_bug.cgi?id=14658
  http://marc.info/?l=linux-kernel&m=125951310317648&w=4

It doesn't look like the proposed patch actually fixed the issue.
Either way that patch is now in 2.6.32 and yet it does not resolve the
ramdisk loading error on my MPB5,4 (btw I'm using a 64bit kernel +
EFI). I will try and do the bisect investigation but I'm still quite
new to git+kernel.org repos so it may take me some time. Because
2.6.32 boots on a MBP4,1 I assume that there is something in 2.6.31+
that does not like newer 64bit EFI Mac firmwares.

Daire