Comment # 102 on bug 913996 from Peter Kirchge�ner

(In reply to James Moe from comment #89)
...
> Disabling the modules ucode-intel and ucode-amd in the Software Manager was
> not sufficient to prevent a catatonic system. It is a necessary requirement
> to include "dis_ucode_ldr" in the kernel parameters at boot time (GRUB2).

I assume that uninstalling ucode-amd is missing to run an mkinitrd.
When I install ucode-amd using yast, this takes quite a while to run the
mkinitrd for the installed kernels. Uninstalling ucode-amd instead is finished
within a second. And the system still hangs after reboot, when dis_ucode_ldr is
not used. I have to run an mkinitrd manually to be able to boot without
dis_ucode_ldr.