iphone 3gs ios 4.1 baseband 5.16.08 unlock

[exon]

Hi,
i have got an iphone 3gs from somewhere and i 've seen that it has ios 4.1 installed on it and the modem firmware is 5.16.08.To unlock it i am willing to install iPad baseband 6.15.If you have any unlock method then please help me.
thanks

 

[willerz2]

Jailbreak and flash the iPad Baseband using RedSn0w. Then install UltraSn0w through Cydia.