Apple has release iOS 4.2.1, but not alone, it has merged some traps with this version for jailbreakers and unlockers with the introduction of a baseband requirement for iOS starting from the newly released iOS 4.2.1. Precisely, if you are using Saurik’s server or tiny umbrella and trying to restore 4.2.1 on an iPhone 4, you will end up in recovery mode and tiny umbrella will not be able to pull you out of recovery.
TheBigBoss: It seems that Apple has decided to put a baseband requirement on iOS. So at this point, if you are using Saurik’s server or tiny umbrella and trying to restore 4.2.1 on an iPhone 4, you will end up in recovery mode and tiny umbrella will not be able to pull you out of recovery. In this case, you will have to restore 4.1 again or you will have to restore 4.2.1 stock and be tether jailbroken. (Of course, I recommend 4.1 and not bothering with 4.2.1 at all). If you are an unlocker, this is a no brainier. Do not update to 4.2.1 even to test it at this point.So we highly recommend to stay on iOS 4.1 and wait until the situation became stable, specially who want preserve their unlock. for now you can check iOS 4.2.1 features form here, and its jailbreak guide with redsn0w 0.9.6b4 from here. Stay tuned
