That's very weird indeed. I just tested in QEMU and no error there. I will try different real PC's tomorrow to see if this is a specific problem with my hardware. Thanks for you help so far and I will update with the results. So I tried as many different PC's as I could find and it turns out it works on all except my test PC, weird :/ I guess it's a problem with the motherboard or something and beyond our control. Thanks for you help!