Bug#623946: grub-pc: M/C unbootable if primary bootable flag not set

[Colin Watson]

On Mon, Apr 25, 2011 at 08:19:39AM +0530, Rustom Mody wrote:
> On Mon, Apr 25, 2011 at 12:35 AM, Colin Watson <cjwatson at debian.org> wrote:
> > On Sun, Apr 24, 2011 at 11:05:07PM +0530, Rustom Mody wrote:
> >> I moved my boot  partition to a logical sector
> >> Running dpkg-reconfigure grub-pc said it had gone through without error
> >> However the disk remained unbootable until a primary (or extended) partition
> >> was flagged as bootable
> >>
> >> It would be good if grub install were to warn about installing to a logical
> >> partition with bootable flag set
> >
> > I don't think this is any of GRUB's business, honestly.  GRUB itself
> > doesn't care whether the partition is marked bootable or not.  If
> > anything cares, it will be your BIOS - but only some BIOSes care about
> > this.
> 
> Exactly so -- in a logical world!
> Unfortunately Intel boards/BIOSes sometimes treat as unbootable a disk
> in which the bootable flag is on in a logical partition -- not so
> logical :D

Yes, I'm aware of that.  I'm not sure how that makes it any of GRUB's
business, though - GRUB doesn't touch the bootable flag (unless
explicitly told to) and doesn't itself care about how it's set.

> Also I agree that this is not a debian problem but primarily a grub
> issue so maybe I take it up there?

What I just said above was that this isn't a GRUB problem.  GRUB is not
causing the problem (the BIOS would refuse to boot *any* boot loader,
not just GRUB).  I don't think it makes any more sense to handle it in
GRUB upstream than it would to handle it in Debian GRUB.

Wouldn't the correct place to issue a warning be in the partitioning
software that allowed you to create this partition layout?  That seems
more sensible and useful to me.

> In summary: a recipe for those reaching here through a search engine:
> 1. grub-install makes an unbootable system if a logical partition is
> marked as bootable

No.  Your system was unbootable anyway due to the partition layout,
regardless of the boot loader that's installed.  grub-install merely
does not help.

-- 
Colin Watson                                       [cjwatson at debian.org]