[coreboot] PS/2 Mouse on KGPE-D16

Has anybody had any success using a PS/2 mouse on the KGPE-D16?

I tried a few PS/2 compatible USB mice, along with an adaptor, without
success and thought that the mice might be to blame but I've just
confirmed a native PS/2 mouse doesn't seem to work either.

I've tried booting directly from SeaBIOS and also with GRUB2 as a
secondary and no combination I try seems to work.