"Searching..." on my iphone 3GS

[overdrivemachines]

I just unlocked my iphone 3GS and I put in my T-mobile SIM and it says Searching... on the top left. I cannot make calls.

I first jailbroke this phone using Greenpois0n (Windows). It said Searching... then I jailbroke using redsn0w 0.9.6rc8 (Windows). It still says the same thing: "Searching...". I also installed ultrasn0w.

My configuration:
Modem Firmware is 05.15.04. Iphone 3GS 4.2.1

Is there a fix for this?

 

[big9erfan]

There is no native unlock for 05.15.04.

There is a way to upgrade the baseband to the iPad baseband that IS unlockable, but there are problems with that solution as well.

 

[overdrivemachines]

Thank you for your response.

Is there any other way? Are there any disadvantages to upgrading the baseband?

 

[Ipheuria]

If you go to the iPad baseband you can only upgrade the firmware using ustom ipsw. You also wont be able to upgrade the baseband until the iPhone baseband is over 6.x... You also wont be able to take it to the Apple Store if you have a problem because like I said you can ony load custom firmware on it. So they will know you're JBen. Did you purposely upgrade the firmware?