What is the UYK menu?
When i originally flashed the silver kindle to 4.0 i had to rename the screensaver folder to get the update to work, but it wasn't greyed out before i did this. The update would just fail. On the black kindle the option to update is simply greyed out.
Another thing is I've now upgraded the black kindle to 4.0.1 using debricking method and a 4.0.1 image, which doesn't have the screensaver hack, still the update is greyed out.
I think the only way i can get this black kindle connecting is to have it running the firmware i believe it ships with which is 4.1.0.