So, is this edit done to the GRUB of my PC, or is it done on the GRUB of each of the VMs that I cannot start? I am guessing it is on the PC side.
Since the latest kernel update on Tumbleweed, my working VMs no longer start. It took me a bit to track it down to the kernel module for VirtualBox failing to start. A reboot takes about 8 to 9 minutes for everything to timeout and restart the PC.
At least my VMs are just for testing and such, so no harm, no foul. I can easily wait till they update the kernel module. For others, that might be a much more critical issue.