Found this post when I googled, I got an AtomS3R yesterday and I have the exact same issue with the display.

Pretty much what @10sor said. Backlight is on but nothing else shows on the display. Tried with UIFlow2 and the examples in Arduino IDE. I've reflashed and reset multiple times, always the same result.

Factory demo works without any issues. The Env III sensor also works, I got output from it in UIFlow2 but the screens is black at all times.