FWIW here's the DMESG from the system I just put in place.
pchb0 at pci0 dev 0 function 0 vendor "Intel", unknown product 0x0bf3 rev 0x04
ehci0: timed out waiting for BIOS
xhci0 at pci2 dev 0 function 0 vendor "Etron", unknown product 0x7052
ehci1: timed out waiting for BIOS
I admit I'm not great at reading DMESGs, but these are the sorts of things that worry me.
