[syslinux] [PATCH] chain.c32: add support for loading GRUB stage2

[Gert Hulselmans]

Thomas Bächler wrote:
>> GRUB's loading mechanism allows to somehow provide stage2 with the
>> selected disk and partition, BSD slice, etc. (ie, to tell stage2 what
>> it's "root" is). I don't yet understand the notation used in that
>> mechanism. Besides, since stage2 images will not necessarily be loaded
>> from the disk (and partition, etc.) they were installed to, it seems
>> best to just use the first disk.
>
> I believe that is not the purpose of stage2's "root". When stage2 is
> loaded, it looks for a file /grub/menu.lst or /boot/grub/menu.lst to
> read a configuration from. My guess is that the "root" in this case is
> the device where it looks for that file.
>
> Without menu.lst, grub will just show a prompt. If I am right, it would
> be very useful to be able to APPEND a "root" so that a chainloaded grub
> can load a configuration file without user intervention.
>

Grub4dos (based on Grub Legacy) can chainload stage2 of Grub Legacy too:
    chainloader --force --load-segment=0 --load-offset=0x8000 --boot-cs=0
--boot-ip=0x8200 (...)/.../stage2

Paul Bolle's patch does the same. So that is good news.

When I wanted to chainload grldr (Grub4dos) with chain.c32 I (Grub4Dos ==>
based on Grub Legacy