Since several service packs for Grub2 has been recently installed, the
boot-selector no longer works via USB keyboard input. 

For example, you navigate to the input line using a PS/2 keyboard. Then press a
key on the USB keyboard, the line is immediately flooded with the correct
letter and the system hangs.

Leap 15.5 (64-bit) and Windows 7 (64-bit) are installed. Since Windows does not
support UEFI due to a bug, the system has to boot in compatibility mode. 

Since PS/2 is not supported by my KVM switch, I currently have 2 keyboards on
my desk. This is somehow impractical. 

The board was installed about 2 years ago.  At that time it didn't work either
(same error). The X570 chip set was relatively new, so I assumed that the
driver for the chip set was still not implemented. 

But since about one year it has worked flawlessly. I would be happy if this
condition can be restored. 

Hardware: Mainboard MSI, MEG X570 UNIFY, AMD® X570 Chip set

Thank you!