Are you using zgemma i55?happy to flash but its doesent seem to be working. Ive downloaded atv 6.4 put it on a USB, turned it on hit reset at the same time, box flashed red and it just boots as normal. ive even changed the file to £forced" from "unforced"
What size USB?
Have you formatted it first?
If you put USB in the box, can you initialise it via menus?