Since 12.2 release opensuse has grub2 as an option to use. Come 12.3 it is the default grub in the installation but you can always choose to use the old legacy grub. As of this time of my blog entry Aug 2013, grub2 is still in development but usable (so they say :P ).
Then if your using the old legacy grub suse has some options to edit the necessary entry in order to boot your system when it has some boot issues.
Sadly if you use grub2 then it is only limited to the following: