Comment 15 for bug 106887

mpwalter, I hope you have a good boot floppy/cd and a backup, because this can get messy :) Actually it shouldn't be any risk at all, only boot sectors will be changed, and if you can boot a grub floppy you can always recover.

- I am not sure if it's possible to use stage1 from Mandriva and stage1.5 from Ubuntu, but you can try.
- the grub command "install" allows to choose any stage1 file. Try "help install"
- the MBR is (hd0)
- you can specify "full path" to a file, for instance if your have set root to Mandriva and needs Ubuntu menu.lst:
 root (hd0,4)
 configfile (hd0,2)/boot/grub/menu.lst
This would be what I asked for in (2) in my previous post, and I suggest you try this first, since it doesn't change anything on the disk. Of course, boot into the Mandriva grub before running these commands.

Then I was thinking something like this for experiment (1).
 root (hd0,2)
 install hd(0,4)/boot/grub/stage1 (hd0) (hd0,2)/boot/grub/stage2 p (hd0,2)/boot/grub/menu.lst
This should install the Mandriva stage1 to MBR and link to the Ubuntu stage2 and menu.lst

I am new to the "install" command myself, and still find the stage1.5 vs stage2 a little unclear, but if you run setup (hd0) you can see what the default install command is, to get an idea.

To reinstall clean Mandriva:
 root (hd0,4)
 setup (hd0)

To reinstall clean Ubuntu:
 root (hd0,2)
 setup (hd0)