Re: Format option for chainloading GRUB from BOOTMGR

[Alexei Podtelezhnikov]

On Tue, Aug 6, 2013 at 1:07 PM, Andrey Borzenkov <address@hidden> wrote:

В Mon, 5 Aug 2013 13:30:04 -0400
Alexei Podtelezhnikov <address@hidden> пишет:

> Hi all,
>
> Thanks to ideas in [1], I managed to chainload GRUB2 core.img from Windows
> 7 BOOTMGR. Here is the three steps.
>

> 1) Create core.img with **full** direct unmounted path to grub directory

> starting from partition, for example
>

> grub2-mkimage --output=./core.img --format=i386-pc --prefix=*(hd0,1)*/grub2
> biosdisk part_msdos ext2
>

More robust is to use embedded config to search for partition UUID.
Hard disk enumeration may change between reboots.

What is the correct syntax to supply UUID in --prefix?

 

Adding something like i386-pc-lnx is relatively trivial from technical
PoV. The main problem is that we need to keep boot code and /boot/grub
directory in think - i.e. both must be updated in one step. Does BCD
configuration need update after grub2.img gets updated?

You do not need to update BCD each time you touch grub2.img. BOOTMGR loads the file from the disk. So once you set up BCD you can forget it until the location of /boot/grub changes of GRUB3 comes along, whichever is first.