GRUB badly broken during upgrade

[Kevin O'Gorman]

On Fri, Oct 5, 2012 at 4:59 PM, Avi Greenbury <lists at avi.co> wrote:
> 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 :)

Let me try to clarify.  I did indeed have two roots on the same
volume, abeit not simultaneously.  The GRUB menu had entries for both
of them that would put me in the system I chose.  In other words, it
was just multibooting two alternative Linux setups.  This was
accomplished by the Xubuntu 12.04 GRUB, which I can no longer access.


>
>> >> 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.

I'll try the supergrub.  I don't want to get too far from what was working.

-- 
Kevin O'Gorman

programmer, n. an organism that transmutes caffeine into software.