[pcwalton]

Itanium was extraordinarily backwards incompatible. There's an enormous gulf between "runs software from the 80s" (which is something the PC platform only pretends to do anyway, because peripherals now are incompatible) and "can't run Windows at all". Breaking v8086 mode wouldn't prevent modern Windows from working (which is in fact why this bug wasn't noticed). You can't even enter it from long mode to begin with!

[merb]

actually my windows 10 installation didn't used uefi. (I had a really old machine). Basically I upgrade/upgraded to ryzen. I don't think it will be easy to migrate to UEFI straight.