GRUB badly broken during upgrade

[Kevin O'Gorman]

On Fri, Oct 5, 2012 at 6:47 PM, Kevin O'Gorman <kogorman at gmail.com> wrote:
> 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.

I tried supergrub with no luck

I've burned a supergrub disk, version 0.9799, the latest not-beta I could find.
Its help did not do that much for me, so I fumbled around a bit.
Because I have several partitions, I chose manual operation
-  GRUB -> MBR & !LINUX! (>-2) MANUAL
-  This gave me
--      selectfile /grub/stage1 /boot/grub/stage1
--      ERROR 15: File not found!

So I tried
-   !LINUX!| (>=2) MANUAL
-   This gave me
--      selectfile /boot/grub/menu.lst /grub/menu.lst
/boot/grub/grub.conf /grub/grub.conf
--      ERROR 15: File not found!

So I tried
-   (ROOT) !LINUX! (>=2) MANUAL
-   This gave me choices
--      It identified the systems on the two root partitions
correctly.  The Xubuntu partition (hd0,1) failed, so I tried Ubuntu
(hd0,6), which also failed, but here I'll give details (the two failed
in very similar ways):
--      It showed me the vmlinux files, I chose the most recent
--      It showed me the initrd files, and I chose the matching one
--      It started booting
--      It gave up waiting for the root device and gave me some
possible causes (I'm  not sure how to check on rootdelay= and root=)
--      It complained about a disk being unavailable and gave me the
UUID it was looking for
--      Then it could not load the /lib/modules file it wanted
--      and dropped me in busybox, which seems to be a simple shell
running in a ramdisk.  It has no /dev/sd* entries, so it seems pretty
useless.

I booted an Xubuntu 12.04.1 live disk
-  with blkid, I verified that the UUID it failed to find is (hd0,6)
aka /dev/sdb7)  There are 3 drives in the system, but only one has a
partition 7, so there was no confusion
-  "grub-install /dev/sda" fails, complaining it "cannot find a device
for /boot/grub (is /dev/ mounted?)"
-  mounting /dev/sdb7 and chrooting to it does not fix this problem

I'm out of ideas at the moment....

++ kevin




-- 
Kevin O'Gorman

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