USB port on a Yamaha receiver? Which model is that? Couldn't find anything about USB on the Yamaha webpage.
Anyway, IF you can use a USB jump drive, logic would state that you should be able to use a hard drive. Whether it's powered internally or externally, I do not know.
Which model Yamaha that has a USB port? Should be info in the manual. I doubt anyone can answer your question unless they know of that receiver, or see the manual.
I'm curious, now.