Aporte original por: oldturkey03 ,
SIMRAN, so the way I understand it, your GSM front end module is off. You can get it [http://www.buyforapple.com/products.php?product=iPhone-4-GSM|from here] if you need a replacement. To replace it, I would possibly treat it like a reflow. also, have a look [http://www.howardelectronics.com/chipquik/instructions.html|on here.] I hope this helps, good luck.