I updated from Opensuse 10.2 to 10.3.
Everything worked fine, except that 10.3 did not boot after reboot.
Kernel message was: "Waiting for device ..."
As the repair option crashed everytime, I searched in the internet but could not find any solution (That's why I write this down now).
In my case the problem was, that I had installed in 10.2 Vanilla kernel 2.6.24 and 10.3 has kernel version 2.6.22.
The updater did not update the kernel automatically. I guess because he "thought" the installed one is newer.
Solution: Manually select the kernel packages for update to the 10.3 Version (2.6.22).
Afterwards the system booted in my case.