Sound's like a dud. Something is wrong with the USB hardware or the 16u2. One final thing to try would be to program the 16u2 via the ISP header, otherwise send it back for replacement.
Sound's like a dud. Something is wrong with the USB hardware or the 16u2. One final thing to try would be to program the 16u2 via the ISP header, otherwise send it back for replacement.