Err looks like you tried 5800 back cover on n900 i asked you to check the 5800 backcover on 5800 and see if it has that nasty flash blinding problem in 5800 ex you can take a photo at night of the sky and see if its pitch black or whiteish
btw i also tried a silicon cover on n900 to hold stuff togther but that needs work i mean i am not enso that i carve out a mugen out of whale bone but i am trying to come up with something that can act as a mugen cover