Can the usb port handle a external drive that runs off just one usb cable? Or are the only external drives that will work are external powered drives? With the hack ATV Flash of course installed.
The USB port should provide power for a suitable 2.5" drive/enclosure combo. The USB standard provides a 5V power line, but not a 12V power line so you cannot run 3.5" drives from it. If you try it, please report back here.