>> Do you remember which choice you chose at this screen ( http://pix
.toile-libre.org/upload/original/1312973605.png ) when you installed
Ubuntu ?

I have performed manual partition of  disk.


I do NOT tring to create dualboot - so it is not like  Bug #1050940  .
The only I want is to load Ubuntu on  GPT partition in legacy mode.
I have set of problems with it which I identify as limitations (bugs?) in GRUB2 
and kernel:
1. ( in grub-install) Grub2 refuse to "grub-install /dev/sda" if protective GPT 
entry is NOT the first.
This bug could be workarounded with method described in bug 2.

2. ( in grub booting - core.img? )I could do grub-install IF protective GPT 
entry is the first, and to rearainge order of records in MBR so it become not 
first - but in this case GRUB failed to detect GPT during booting.
During boot shown:
error: no such partition
grub rescue> ls
(hd0)

3. ( in grub-install) IF I do protective record start from sector 2048 -
then I could install GRUB in "biosdisk" (?) mode but in this case it
installed it data (102 sectors) starting from sector 1 and so corrupt
GPT header. I assume that is stage1.5/core.img data ?

4. ( in kernel?) with setup when GPT protective record is NOT first and starts 
from sector 2048 kernel not able recognise hybrid partition table. in dmesg I 
see:
[sda]: unknown partition table
same time gdisk sees correct GPT and hybrid MBR  


Most correct approach - will be to resolve bug 2. But guess  that reqires 
re-working ASM code.

For now I am trying diferent approach - boot core.img in biosdisk mode and then 
load correct module (part_gpt) through (hd0,msdos2) and then perform father 
actions through (hd0,gptN).
For that I need to find way to force GRUB install it stage1.5 not to sector 1 
(resolve bug 3) .
I guess for that needed to tweak (or hack) boot.img to point it to new place of 
core.img


I could easily migrate stage1.5/core.img to diferent place with "dd" - but I do 
not know how point that place for stage1/boot.img

I see that size of stage1.5 is 51kB(102 sectors) so if I place it
starting from sector 1901 it will be good enough. Another option is to
use partition gpt12 (EF02) but then either grub must recognise GPT
partition table (see bug 2) or point for stage 1 it location in biosdisk
mode.

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https://bugs.launchpad.net/bugs/998097

Title:
  Grub2 not recognise GPT when presence hybrid MBR

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