heiligekuh
Beginner
This comment really helped me. I was getting white screens after successful ROM/Key writing, and this pushed me back to remove all the boards and reinsert again.That really sounds like a main program ROM issue as @Darksoft mentioned earlier.
The lighter screen is usually what you see if main program ROMs are missing, pure black like the second image looks to me like the code is running but it's crashing.
Found the bent pin that wasn't seated properly! Of course, I was tired and managed to break it off the program ROM daughter board in the process.
But at least that's a clear and fixable problem.
--andrew