Try this: In YaST Boot Loader under the Boot Loader Installation tab, install grub to the "root partition" boot sector. In that same dialog window, go to Options and check the box for "Write Generic Boot Code to MBR". Make sure the "Set active flag" is also checked. Generic master boot code will chain to the active partition boot sector, which will in turn call grub stage2 (this is the Windows "chain load" method, as opposed to having grub stage1 in the MBR which loads stage2, i.e., the "direct" method).
On a different tack, and just on a hunch, is it possible at all that after the upgrade your system starting seeing the SATA drive as the first drive and the IDE as the second? Take a look at your /etc/fstab - if it is mounting by "device ID" (the new default method which identifies drives by serial number) rather than "device name" (i.e., "/dev/sdb"), the order could have been changed without noticeable effect (except in grub where only device-name is used, which would then fail).