Hey!
Noticed this with my IP35 pro, when its booting up, apart from the very first hit delete for bios config bit, like if windows says 'press a button or wait' my keyboard doesnt respond. When windows has loaded its fine though.
This can be a nuisance and when setting up a new OS I need to get my trusty mini ps2 keyboard out because the USB one just doesn't register. Its fine with other motherboards though.
I've noticed the same phenomenon with my girlfriend's nf-m2n board too. (again, trusty mini ps2 to the rescue). Any suggestions?