Re: grub-probe fails to find PC partition due to Apple disklabel

[Robert Millan]

On Mon, Jul 28, 2008 at 11:20:26PM +0200, Robert Millan wrote:
> On Mon, Jul 28, 2008 at 03:25:00PM -0400, Chris Knadle wrote:
> > On Monday 28 July 2008, Felix Zielcke wrote:
> > > Am Montag, den 28.07.2008, 14:41 -0400 schrieb Chris Knadle:
> > > >    However on the last test I did make an error and left out the -d
> > > > option to grub-probe, and that's required for the grub-probe to succeed,
> > > > so unfortunately the output I posted is erroneous.
> > > >    A new one is attached which has Robert's patch applied -- it does
> > > > succeed in finding the partition, but unfortunately we can't fix the
> > > > problem this way because I believe it makes Apple partition detection
> > > > *always* fail.
> > >
> > > Urgs, yeah didn't see that.
> > > You have to use -d if you give a device.
> > > Why do you think that with this it will always fail?
> > 
> >    Because the test that the patch does is to check for an HFS+ filesystem 
> > magic number against the first 2 bytes on the drive, which contains a jump 
> > vector for the Grub stage1 binary.  i.e. in order for the test to pass, 
> > Grub 
> > has to be unbootable.
> 
> My check has nothing to do with HFS+, it's based on the header magic number
> (0x4552), which differs from the partition magic (0x504D) but also from the
> HFS+ magic (0x482B, 0x4858).
> 
> Please could you test it against an apple partmap?

Actually, it was simple for me to test, since Parted supports apple/mac
partition tables.  The test I added succeeds with the partition I created,
so it must be good.

I just checked that in.  Thanks a lot for the long & tedious debugging process.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."