Re: workaround install boot on btrfs with windows partition scheme

[Chris Murphy]

On Nov 1, 2014, at 11:27 PM, Andrei Borzenkov <address@hidden> wrote:

> В Sat, 1 Nov 2014 14:35:57 -0600
> Chris Murphy <address@hidden> пишет:
>> 
>> Why not have a dedicated partition with MBR type code for core.img, 
>> equivalent to BIOSBoot currently used on GPT? freedesktop.org has a proposal 
>> to use type code 0xEA for this purpose (in part). The boot.img code in the 
>> MBR can arbitrarily jump to any LBA, so 0xEA doesn't need to be a primary 
>> partition does it?
>> 
> 
> It is rarely needed in simple cases; in complicated cases (btrfs or
> LVM) we already have space dedicated for core.img. It seems more
> logical to use this space.

Well actually it isn't rare in simple cases. The most common case on Linux is 
booting from ext which grub won't embed to either without --force. So we have 
to have core.img embedded somewhere else. UEFI it's a fixed location. BIOS+GPT 
it's a fixed location. Only on MBR is it in an unreserved location or forcibly 
embedded - that's really  where the problem is. It seems a lot simpler to 
constrain the MBR options down to only a reserved partition just like elsewhere 
where it's now much simpler because it can only properly go in one location.


> Also you still need to tell grub-setup to use this special partition at
> which point why not extend it to support arbitrary location for
> core.img? It could be made check partition type and not refuse to
> install on raw partition for special 0xEA type then as a bonus.

I never tell grub-setup to use BIOSboot partition type. It always just finds it 
automatically.



Chris Murphy