update grub + 2 ubtuntu installs with shared /boot

[Philip Lawatsch]

Hi,

I've run into a not so nice problem today.

First my setup:

I have

a amd64 system (dapper) installed into /foo, a
a i386 system (dapper) installed into /bar and
a partition mounted as /boot by both (!) installes


Now my problem is that when update-grub is called on one system it will
happily trash the other systems entries in menu.lst.
What happens is that it seems to completely rewrite the entries and thus
does not consider that the kernels have different root parameters.

So, if update-grub is run on 32 bit then the next time i boot the 64 bit
kernel I'll end up in my 32 bit system (with a 64 bit kernel though) and
vice versa.

Would someone know a fix for this problem _except_ creating seperate
/boot dirs and install grub 3 (2 would work too I assume) times?

I'd love to keep the automatism of updating menu.lst but since I onced
managed to boot into my 32 bit system with a 64 bit kernel and then
started to wonder why nothing (of my own stuff, not of the system) I'd
like to avoid this at all costs.

kind regards Philip