Help needed to unlock iphone 4 running iOS 4.3

[born2njoy]

Hello Experts

I would like to unlock my iphone4 running iOS 4.3 version with baseband 05.16.01. It is not jailbroken yet. Could you please advise which tool should be used to jailbreak and unlock my phone ?. Can Jailbreakme 3.0 be used to JB and Ultrasnow be used to unlock the carrier ?. Thanks for your time.

 

[jeffrey1027]

Your baseband cannot be unlocke with ultrasn0w. Please google gevey unlock sim. They are your only option to unlock your iPhone no jailbreak needed

 

[born2njoy]

Help needed to unlock iphone 3GS running iOS 4.3

Thanks jeffrey for your response. I'm really sorry for the incorrect model specified. Mine is actually 3GS not iphone 4. Is it possible to use custom IPSW to upgrade the version to 4.3.3 and unlock it using Ultrasnow 1.2.3 ?. That way, can my baseband be preserved or would it get updated to 6.15.00 and I would lose the GPS functionality?.