From the Readme under ftp://ftp.iphonefix.de/Firmware System Custom/README
"All Firmware in here are activated and jailbroken.
DO NOT USE IT IF YOU PLAN TO USE A IPHONE WHICH IS FACTORY UNLOCKED OR LEGAL ACTIVATED BY iTUNES!"
Wonder if this won't work with a legally subbed AT&T?
Token
It's the typical "Legal" information. Worked fine on my AT&T 3GS. But still had ICY, and it had the custom boot logos.