Gevey SIM the universal tool used to run carrier locked iPhones and iPads on any network has been disabled in Apple’s latest update for iOS: iOS 5 Beta 2. The Gevey SIM is a SIM card itself but is quite thinner, both the Gevey SIM and the carrier’s SIM have to be inserted into the device together.
MuscleNerd a famous hacker who is responsible for quite a few jailbreak shared the news today on his Twitter.
it’s surprising Apple closed Gevey interposer hole in b2 rather than waiting until final (maybe they were under pressure)
So if you want to use your Gevey SIM your only choice is to downgrade to an iOS 4 version which can only be done if you had preserved your baseband.
Source: @MuscleNerd