I am recently jailbroken & unlocked on an iPhone 3G, version 3.1.2 & with firmware 05.11.07. I used redsn0w to jailbreak, ultrasn0w & blackra1n to unlock for use with T-Mobile. Before successfully unlocking the phone with blackra1n, I attempted to unlock it by using yellowsn0w to unlock from the Cydia Manage screen. I have since deleted yellowsn0w. Everything is operating and functioning as expected except when I open Cydia I get an error message that reads as follows: Error Refreshing Data, GPG error:http://apt9.yellowsn0w.com/ Release:The following signatures were invalid: NODATA1 NODATA2 Failed to fetch http://apt9.yellowsn0w.com/./Packages.bz2 sub-process/bin/bzip2 returned an error code (2)

Thank you for all of the great information provided here on this site from veteran developers. Nothing like having a new an improved Iphone without any dropped calls!