The SAM unlock tool just like an bomb to the iPhone community, folks who were locked in stubborn basebands 4.11.08 and 4.12.01 finally got a solution. And damn it, it's free! However, if you know unlock, you should know there is someone would not be happy to see that, GEVEY which announced its new unlock product on the right next day after SAM floated up, have given 5 reasons to choose Gevey SIM instead. Which one you should choose to unlock your iPhone?
Here are the 5 reasons:
REASON 1: First off, the SAM solution exploits a vulnerability found on the iTunes activation server to unlock your iPhone. If or when Apple updates the iPhone activation server, this SAM unlocked process will most likely no longer work. Our GEVEY Ultra hardware solution doesn’t rely on the iTunes activation server and will not be affected should any changes to the iPhone activation server be made by Apple.
REASON 2: The SAM unlock requires a jailbroken iPhone. GEVEY SIM Interposer works on both jailbroken and factory locked iPhones, depending on which model you own.
REASON 3: The SAM solution will not work on blacklisted iPhone models. Since the SAM solution requires your phone to be activated through iTunes, your iPhone IMEI must not be blacklisted. The original service carrier may blacklist an iPhone for many reasons, including theft, loss, or delinquent payment. GEVEY™ hardware solutions don’t require iTunes activation and can unlock blacklisted handsets.
REASON 4: The SAM unlock requires tethering or a computer connection in order to get your iPhone free from carrier restrictions. Most GEVEY solutions are plug-and-play, which means you don’t need to connect you iPhone to a computer in order to unlock it.
REASON 5: The SAM can only unlock one SIM card at a time and if you own multiple SIM cards or plan on using other SIM cards in the future, you’ll need to go through the unlock process on your phone every time you switch SIM cards. On the other hand, the GEVEY hardware solution unlocks the phone permanently, as long as your GEVEY turbo SIM is installed. With GEVEY, users can change SIM cards as often as they like. The GEVEY hardware unlock for the iPhone 4 allows users to store up to 10 SIM cards on a single GEVEY turbo SIM.
Now here is our advice, we know that few days before SAM floated up, the US carrier AT&T has announced to unlock their iPhone - this is our first advice, since it is an official way to get your iPhone unlocked for life.
The SAM method proved to be useful for those who failed to get their iPhone IMEI unlocked via AT&T’s official route. SAM works by tricking Apple activation servers, and it unlocks jailbroken iPhone 4S, iPhone 4, iPhone 3GS running on iOS 5.0, 5.0.1, 5.1. But finally, it requires jailbreaking, so it's a risk. However, it could still be the second priority for the fact that it comes free.
If none of the method works for you (highly unlikely), go for Gevey SIM, which cost almost $50.
Just for advice. You can read the original applenberry's post here.