Originally Posted by Solaris81
What is the UYK menu?
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.
UYK is a common acronym used here at MR, for "Update Your Kindle".
It makes sense that firmware updates older than 4.1.0 may not support the new K4B serial number prefix. In fact, I think that the hack update packages needed to be modified to support the new serial number prefixes as I recall). The older firmware updates may not support the new serial number, which would explain the grayed-out UYK menu.
So, we may need a newer firmware image to properly debrick a K4B.