updated 10:35 am EDT, Wed June 23, 2010
Each device carries unique burdens
A new version of PwnageTool, 4.01, has been released by the unofficial iPhone Dev Team. The software now jailbreaks the final version of iOS 4, which was released on Monday. Users must not, however, have installed the official upgrade if they have used Dev Team tools in the past for activation or carrier unlocks.
Many other limitations exist, namely that the hack will work only with the iPhone 3G, iPhone 3GS and second-generation iPod touch. Each device also has its own installation conditions; a 3GS, for instance, must be untouched by Apple's new bootrom or the Spirit jailbreak. With the 3G or second-gen Touch, people have the option of using redsn0w instead.
Actually unlocking an iPhone for use with unofficial carriers requires ultrasn0w 0.93, which should now support all basebands from v04.26.08 onward. To complete an unlock, people must run PwnageTool 4.01 and install ultrasn0w later, using Cydia. None of the Dev Team software is yet compatible with the iPhone 4, which is already shipping to some homes.