My screen did the same with randomly going black. Reverting firmware resolved that issue for me. I noticed my keyboard didn't work the other day, so i wonder if my USB is messed up as well. I haven't troubleshot that at all yet.I am pretty sure I have it connected that way. Tech support has been great - and the issue with the screen going black is the GROM unit itself as the Android OS freezes. The USB port 1 also became inoperable.
I am going to revert back firmware to see if that resolves the issue. On the other hand I was able to get the Factory USB port to work with Grom!