Just bought and installed the unit; updated to latest firmware as suggested during start-up. The unit refuses to play almost any mp4 file I provided (just played 1 or 2 out of 10+). Files are provided by means of a USB stick: I see the files but when attempting to play them, the unit holds on for a while (in some cases, but not all, it recognizes video length) and then reverts back to the list.
Shows similar problem also playing some mkv file.
Honestly I have to say I am very disappointed: bought the product to get rid of problems I had using other means such as BR player and/or TV itself to play this kind of video files and, as such, it is proving totally useless.