Now again I am back with another article on How to use Gevey SIM to unlock iPhone 4 without jailbreaking it. Before all that I would like to tell you that use of GEVEY sim is banned in USA and other countries too. I do not know about other countries but using GEVEY sim may lead to serious problems as to activate GEVEY sim you need to call up 112 and that gets transfered to 911 and calling 911 for no reason is illegal in USA so I would advice you to not to use this technique to unlock your iPhone 4. Had I been at your place, I would have never done it as i would not like to play with law and order in any ways. So I have already given disclaimer, do not try this.
Now as we know GEVEY ISM card is used to unlock Phone 4 basebands 1.59.00 / 03:10.01 / 02.10.04 / 04.10.01 having iOS 4, , iOS4.2, a iOS 4.3, iOS 4.1, iOS4.2.1. So here is the detailed tutorial on how to How to Use GEVEY Sim to Unlock iPhone 4 without Jailbreaking your iDevice. GREY sim turbo is also available for $70 but one of the Apple developers has already announced that use of GREY sim is illegal and should be banned in USA. So use this trick at your own risk.