updated 11:55 am EDT, Mon March 28, 2011
Carrier unlock still unavailable
Hackers have reportedly already managed to jailbreak iOS 4.3.1, despite the firmware being released just last Friday. The main technique so far requires a Mac running a special bundle of PwnageTool 4.2 including Universal Ramdisk Fixer, as well as a utility called tetheredboot. iTunes must already be updated to v10.2.1.
Several limitations exist with the hack; it is relatively complex, for instance, and still demands temporary tethering with a computer. It has also yet to be tested with the iPad 2, and does not upgrade the baseband on cellular-equipped devices. There is likewise yet to be a carrier unlock available for iOS 4.3.1, so people using a device on an unofficial carrier are encouraged not to upgrade to the firmware, stock or otherwise.
Special instructions are involved in jailbreaking a first-generation iPad or a fourth-generation iPod touch. The crack does however support "hacktivation," as well as the latest version of Cydia. Cydia one of the primary means of distributing unofficial apps for jailbroken hardware.