Serious GRUB booting problem after install Ubuntu 9.10beta for testing it.

[Goh Lip]

Tom H wrote:
> Luis Maceira <luis_a_maceira at yahoo.com> wrote:
> 
>> I installed 9.10 beta for testing it on an external
>> USB HDD partition (/dev/sdb7), and I have 9.04 on
>> /dev/sdb5 (where the default GRUB stage2 is), I
>> also have 9.04 on the internal SSD drive (partition
>> /dev/sda3). Now I am not able to boot Ubuntu 9.04
>> on my internal SSD drive.
> 
>> When I disconnect my external USB HDD the booting
>> process gives me:
> 
>> GRUB loading...
>> error: no such disk
>> grub rescue>_
> 
>> When the external USB HDD is connected and I call
>> the GRUB menu and it appears, the system (9.04) on
>> the internal SSD appears normally on the GRUB menu
>> (I think everything is OK) choose booting the SSD
>> but then the warning:
> 
>> Error 17 : cannot mount selected partition
>> Press any key to continue...
>> (and return back to GRUB menu)
> 
>> From my working systems 9.04 and 9.10 on the USB
>> HDD I mount the filesystem on the internal SSD and
>> everything appears OK even the /boot/grub directory,
>> so in my opinion the installer of Ubuntu 9.10 beta
>> messed up with GRUB stage 1 on the MBR of the internal
>> SSD and the way to the right partition /dev/sda3 is
>> lost.
> 
>> Any way to revert this? without installing Ubuntu
>> from scratch on the internal SSD.
> 
> Since you are at the "grub rescue" prompt when you try to boot from
> your internal SSD and no external HD connected, you must have grub2
> installed on your SSD.
> 
> grub rescue> ls
> 
> It should list your disk and its partitions.
> 
> grub rescue> root (hd0,X)
> Where X is your "/" partition (or your "/boot" partition, if it is separate).
> 
> grub rescue> ls /boot
> To confirm that you have "rooted" the correct partition.
> If you have, you should see your kernel, initrd, etc and the grub directory.
> If not, do another "root (hd0,X)" and try again.
> 
> Once you have the correct "root (hd0,X)".
> 
> grub rescue> insmod /boot/grub/normal.mod
> To go to the normal grub prompt.
> 
> grub> insmod /boot/grub/ext2.mod
> To load ext2 module.
> 
> grub> ls /boot
> If you cannot see the output of the previous "ls /boot" and cannot
> remember the file names of the kernel and initrd.
> 
> grub> linux /boot/vmlinuz-2.6.31-13-generic root=/dev/sda3 ro
> To load the kernel.
> 
> grub> initrd /boot/initrd.img-2.6.31-13-generic
> To load the initrd.
> 
> grub> boot
> To boot.
> 
> You should boot into your SSD install.
> 
> Once booted, you should run "grub-install /dev/sda" to ensure that
> your SSD's grub.cfg is updated/corrected and you should then check it.
> 
> Then connect the HDD and run "update-grub" to add the two HDD installs
> to the SSD's grub.cfg.
> 
> (I would also check that the device.map and grub.cfg disk references
> correspond.)
> 



Tom, won't it be easier for him at the grub> prompt to type
configfile (hd0,3)/boot/grub/grub.cfg


to boot up his sda3 9.04 partition if it is already in grub2?

Regards,
Goh Lip