Need help unlocking US iphone 3g in India

[bigindy]

So i recently came back to india and i bought an iphone 3g before i left. The firmware version is 4.2.1. I followed the Redsn0w jailbreak then ultrasn0w unlock. But the problem is whenever i put in my sim card ( which is !dea sim BTW) the iphone just keeps turning on and off and wont connect. What is the problem? is there another unlock i can possibly do after restoring. Any help would be appreciated, Thanks!

 

[Applejuiced]

Try a restore and rejailbreak.
But if the phone keeps shutting off and restarting it might be a hardware issue.

 

[bigindy]

Will do. But its not the hardware because when the sim card is out it works perfect. Would a downgrade to 4.1 or. 4.0 help maybe?