A:Answer I installed a thumb drive. Had to format with the Fire-TV app to recognize the memory. still, Won't allow use for app storage, i suspect the TV DVR uses this memory for live TV, not useful for anything else, access was blocked.
The Fire-TV seems to have limited access, you might have to root in order to have more rights.
I played video from a thumb drive with the Media player, not FireTV. Also accessed video from a router harddrive.