Hey when I unlock it I was using the redsnow 0.9.9b7b so I did the custom IPSW to keep my baseband ,after that I restored my iphone in itunes with the IPSW. With my iphone restarted I went to the Jailbreak in redsn0w and installed it, when my iphone reboot again the the Picture of the redsw0n appers in the screen later the "loading circle" appers and i wait about 5 minutes and it get "frozen", so i went to the redsn0w again and did the DFU and restart it with the Just Boot tool.

Sorry my bad English...

I'm using Iphone 3GS with IOS 5 and baseband 6.15.00 Semi Tethered and it works great for me, no problems until now !