It was met with great joy when it was learnt that Gevey SIM interposer could unlock iPhone 4 baseband 2.10.04 and 3.10.01 by forcing baseband activation through the emergency dialer. It was also met with great joy when we learnt that Gevey SIM can unlock iPhone 4 baseband 2.10.04 and 3.10.01 in US as well. However, we were never quite sure about its legality. MuscleNerd of the iPhone Dev Team has clarified on twitter that iPhone unlock via Gey SIM interposer is illegal.
Why Gevey SIM iPhone unlock is illegal? Well MuscleNerd clarifies that Gevey SIM dials 112 (emergency number) then hangs up. Gevey SIM interposer unlocks iPhone 4 basebands 1.59.00 / 03:10.01 / 02.10.04 / 04.10.01 running iOS 4, iOS 4.1, 4.2, 4.2.1 and iOS 4.3 without the need to jailbreak your iOS device.
That “dial 112 then hang up” in gevey http://is.gd/FGNeJi is illegal in USA, and probably other countries. Buyer beware.
So there is a high probability that carriers will block Gevey SIM because of the fact that it calls emergency numbers and hangs up. MuscleNerd has also confirmed that there is no way that Gevey SIM interposer unlock for iPhone 4 can be made legal.
So the best way to unlock iPhone 4 in the near future is probably going to be through the yet to be released Ultrasn0w 1.3 or the 40 bit NCK hack that the iPhone Dev Team is currently working on.