Comment # 7 on bug 1021319 from Josef Reidinger

(In reply to Claude Diderich from comment #6)
> I do not have the file /boot/grub2/grub2.cfg as I am running grub (0.9
> version and not grub2). Does kernel settings only work with grub2?

yes, only grub2 is supported by yast2-bootloader (it was done already in Leap
42.1 and was part of unifying bootloaders, as grub2 works currently in all
supported architectures).
What you can do is set bootloader to none ( in /etc/sysconfig/bootloader or in
yast2-bootloader ), but still kernel settings won't work. and you need to
modify /boot/grub/menu.lst on your own.