My friend has bought unlocked iphone 3g 2.1 FW with turbosim 3months ago.
then yesterday i updated firmware using itunes 8.1 to 2.2.1 and jailbroken.
then as it wasnt unlocked, i downgraded back from 2.2.1 to 2.2 and jailbroken and as it has Baseband 2.30.03 and bootloader 5.09, it can't be unlocked with yellowsnow.

now, plz tell me way to unlock or way to downgrade bootloader so i can downgrade baseband and unlock my phone?
can i still unlock it using turbosim i have? how to use it plz tell me if it's possible..
rightnow my iphone is like ipodtouch as it's jailbroken but not unlocked.

i hope there must be some way..
Thanks...

Please use the search function before posting as this question has been answered many times.

There is no known exploit in bootloaders 5.09 and above that allows a baseband downgrade which is why only bootloader 5.08 works. I regret to say that until the 3.0 software comes out (within the next couple of weeks) and the dev-team find an exploit for unlocking, you are stuck with an ipod touch rather than a iPhone.

I am not familiar with sim unlocks so I cannot guarantee it will work, look here for more info:

http://www.hackint0sh.or/forum/f124/

Hope it helps.