[lug] Grub question

Collins Richey crichey at gmail.com
Sat Nov 11 06:16:07 MST 2006

On 11/10/06, Kenneth D. Weinert <kenw at quarter-flash.com> wrote:
> Lee Woodworth wrote:
> > Ken Weinert wrote:
> >> Lee Woodworth wrote:
> >>> Ken Weinert wrote:
> >>>
> >>>> Well, I'm not sure how I did it, or what exactly I did, but grub is sort
> >>>> of non-working right now.
> >>>>
> >>> When this has happened to me, reinstalling grub on the boot drive
> >>> has fixed things.
> >>>
> >>> (I have a /boot partition on hda1, system is on hda2, grub boot sector
> >>> on hda)
> >>>
> >>> # grub
> >>> root (hd0,0)
> >>> setup (hd0)
> >>> quit
> >>>
> >> I'll give that a try when I get home tonight and let you know if that
> >> fixes it. If not I'll post up the info the other responder asked about
> >> for further discussion.
> >>
> >> Any ideas on can cause this temporary insanity?
> >>
> >> And no, I've not added/deleted drives or partitions, just compiled up a
> >> new kernel and tried to add it to the boot menu. Yes, that implies that
> >> I messed up the boot menu somehow, but I've not yet seen it and I didn't
> >> keep a copy of what it looked like before (why should I? what could go
> >> wrong? :)
> > This has happened to me when I changed /boot/grub/grub.conf to add a new
> > kernel line. I suspect that grub.conf moved to a different set of blocks
> > when the file was rewritten.  It appears the early boot stage has the
> > config file location hard-coded as  block addresses so it didn't know
> > where the config was anymore. The grub setup command looks for the grub
> > boot code and could be calculating block addresses that it inserts into
> > the early stage boot loader.
> Yes, I had added a new kernel line before this madness started. The good
> news is that re-running grub as said before restored it to a working
> condition.
> Thanks to all for the assistance - it's much appreciated.

I have also seen this behavior after grub software updates. I have a
multi-boot system, and occasionally I have to boot another distro to
fix a problem. My CentOS4 distro, for example, does not always produce
a bootable grub when running grub setup. Not too surprising, since
CentOS4/RHEL4 is pretty aged at this point.

Collins Richey
     If you fill your heart with regrets of yesterday and the worries
     of tomorrow, you have no today to be thankful for.

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