GRUB badly broken during upgrade

[Avi Greenbury]

Kevin O'Gorman wrote:
> On Fri, Oct 5, 2012 at 3:28 PM, Avi Greenbury <lists at avi.co> wrote:
> > Kevin O'Gorman wrote:
> >> I had a system with a working Ubuntu 11.04 and Xubuntu 12.04.
> >> I went to upgrade the Ubuntu to 11.10, and all seemed well until I
> >> went to reboot.
> >> It got confusing after that.  It looked like all of the right kernels
> >> were listed, but they all went to the same root.
> >
> > What do you mean by this? Each listing should generally be the same
> > root (both by grub's definition of 'root' and the kernel's).
> 
> When I had just installed Xubuntu, the grub menu would show its
> 3.0.0-26 kernel at the first two lines, followed by memtest, then the
> Ubuntu 2.6.x kernels with an explicit root for Ubuntu.  The 3.0.0
> lines would boot to Xubuntu, and the 2.6 lines to Ubuntu.  I'd like to
> get back to that state.

I'm still not sure I understand. Just to be clear, your system and its
kernels are all on the same volume? That being the case, when it
worked you cannot possibly have had more than one of any of the things
I can think of that I'd call 'roots'. That being the case, I don't
think it matters what we call them :)

> >> I got in a rescue mode, and tried another update-grub.  Again it
> >> seemed to work, but now grub goes directly to
> >>   grub rescue>
> >> and I have no idea what to do there.  So I'm writing this on another
> >> system, on which I'm not likely to upgrade the Ubuntu any time soon
> >> 8o)


Right now, on boot, your system goes straight to a grub rescue prompt?
(as in the prompt is 'grub rescue>')? That implies a broken grub and
the easiest way round that is normally to boot from a grub CD or DVD
and reinstall (or inspect) it from there.

The Super Grub Disk is popular and here:
  http://www.supergrubdisk.org/

But I've found that there's a few sets of hardware on which that wont
boot but Grub 1 will. I've an ISO for that here:
  http://avi.co/s/grub1.iso

If you do get it to boot, could you let us know what you did? And, on
trying another grub-install how you invoked it and what it said.

-- 
Avi