Re: Grub rescue

[David WE Roberts]

On Sun, 24 Mar 2013 23:47:24 +0400, Andrey Borzenkov wrote:

> В Sun, 24 Mar 2013 16:58:55 +0000 (UTC)
> David WE Roberts <address@hidden> пишет:
> 
>> On Sun, 24 Mar 2013 16:14:48 +0000, David WE Roberts wrote:
>> 
>> > Should grub rescue started from an MBR disc be able to see GPT
>> > partitions?
>> 
>> 
> In rescue mode grub has only drivers that are built into core.img. If
> you used grub-install, core.img contains only enough drivers to enable
> access to grub partition (where /boot/grub is located).
> 
> 
>> /dev/sda 64GB MBR SSD with Windows 7 64 bit, and GRUB2 as boot loader.
>> /dev/sdb 750GB MBR HDD with Ubuntu installed - GRUB2 chain loads from
>> /dev/
>> sda. /boot/grub is on this drive.
>>
>>
> So core.img will have only MBR handler.
>>  
>> My main problem is that I would expect grub rescue to list all the
>> partitions it could see
> 
> Which is exactly what it does. It can see (or better, parse) only MBR.
> 
> 
>> So can someone please tell me if what I am doing is not catered for, or
>> which simple step I've missed out.
>>
>>
> 
> If you still can boot in original configuration, reinstall grub while
> explicitly adding part_gpt:
> 
> grub-install --modules=part_gpt ...
> 
> If you cannot return to original configuration - just follow boot
> recovery procedure for your distro.


Thanks Andrey - simple when you know how!

Is there any reason why GPT support could not be included as standard?

I am probably swimming in a very restricted pool, but it seems that the 
main two disc partitioning schemes at the moment are MBR and GPT so if I 
can update core.img with a GPT handler then it mustn't be too hard to ship 
this as standard.

Whatever, I will give this a go.

My main problem has been that 95% (or more) of the online documentation 
has started at the point where you have located the grub configuration and 
started loading extra information.

Perhaps nobody else is trying to add a big disc to a dual boot 
configuration and change it from MBR to GPT.

Thanks

David