Note: A similar description can be found at Pimp my Suse.
The Installation worked mainly as usual. It only failed at writing grub into the MBR, which is absolutely unacceptable. I had to install an option for the boot loader in an older distribution (10.1) to get 10.2 started. After that everything worked again as expected.
The reasons for grub not working could be found in /boot/grub/device.map, which listed the following device
which means /dev/hdc and is of course is a senseless entry. The file should have listed the following which is the content of “/boot/grub/device.map” in openSuse 10.1
In the end I copied the /boot/grub/menu.lst from openSUSE 10.1 and changed the parameters for the other partition containing openSUSE 10.2.
# Modified by YaST2. Last modification on Mon Mar 12 23:09:41 CET 2007
title OpenSuse 10.2
kernel /boot/vmlinuz root=/dev/hdc5 vga=0x31a resume=/dev/hdc3 splash=silent showopts
title Suse Linux 10.1
kernel /boot/vmlinuz root=/dev/hdc6 vga=0x31a resume=/dev/hdc3 splash=silent showopts
title windows 1
title Windows 2
map (hd0) (hd1)
map (hd1) (hd0)
###Don't change this comment - YaST2 identifier: Original name: floppy###
The Installation of grub is described in grub installation