Bug#467501: grub-pc: Fails to cleanly upgrade a grub legacy box with RAID1

[Robert Millan]

On Thu, Feb 28, 2008 at 02:23:17PM +0000, Jonathan McDowell wrote:
> On Thu, Feb 28, 2008 at 01:22:00PM +0100, Robert Millan wrote:
> > Please provide the output of the following commands:
> > 
> >   sudo dd if=/dev/sda bs=1 count=2 skip=76 | od -tx1
> 
> meepok:~# dd if=/dev/sda bs=1 count=2 skip=76 | od -tx1
> 0000000 ff 00
> 0000002
> 2+0 records in
> 2+0 records out
> 2 bytes (2 B) copied, 7.1382e-05 s, 28.0 kB/s
> 
> >   sudo grub-setup -v "(hd0)"
> 
> meepok:~# grub-setup -v "(hd0)"
> [...]
> grub-setup: info: setting the root device to `md0'
> [...]
> 
> It is. I not that grub-setup claims to be setting the root device to
> md0;

Considering that per spec it is impossible to set the root device to md0,
one could find that amusing :-)

The culprit is at:

  if (root_dev->disk->id != dest_dev->disk->id)
    *boot_drive = (grub_uint8_t) root_dev->disk->id;

which isn't designed to hold more information than a 8-bit integer.  Clearly
this needs some adjustment.

We're discussing how to fix this in upstream mailing list.

> I'm currently at work and the machine is my home box, but I'll try
> rebooting tonight to see if it now boots without intervention.

Don't bother, it won't boot.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)