Hi, I've used my ATV2 box with my LG UV800B since last year, with no issues whatsoever. However recently I updated the OS to the latest available firmware for a 2nd gen ATV, and suddenly it will no longer give me a picture on a 4KTV. The standard HD television at my friends gets a picture okay, but my LG 4KTV since the software update doesn't even receive a signal, never mind a picture! I have tried DFU in iTunes and restoring the device, which doesn't cause an issue. However the moment it's put back into the telly, I get no results. Any ideas? Thanks, Ben.