iPhone Dev Team recently released the latest version of Redsn0w, which is the Redsn0w 0.9.7b1, that serves as the back-up plan for the iOS 4.2.1 untethered jailbreak. This latest version of Redsn0w can be used to jailbreak iPhone 4, iPad and iPod Touch 4G with iOS 4.2.1. However, it is important to note that the Redsn0w 0.9.7b1 is only for beta testers as there are still some known issues that need to be addressed.
Go over the complete information provided by the iPhone Dev Team before trying out the Redsn0w 0.9.7b1 on your iDevices.
* This is a beta tester program. It’s not a general release! Things can go very wrong, so please don’t even consider testing if you have pictures or other media on your device that you haven’t backed up!
* For the same reason, please don’t participate if you rely on the ultrasn0w carrier unlock. Wait for the final version!
* Until we fix some sandbox issues with bluetooth, the bluetooth functionality is disabled.
* This very first beta1 is limited to iPhone4, iPad, and iPod touch 4G.
* Cydia must have your 4.2b3 SHSH blobs saved on file. (As we approach a general release, we’ll provide a way to let you use locally saved hashes too).
* You must already have the usbmuxd software installed and running on your Mac (this requirement will eventually go away too). The correct invocation of the relay is just as that page says: “./tcprelay.py -t 22:2222”. If the relay isn’t installed or running correctly by the time the redsn0w ramdisk has started, you’ll need to restore to stock FW again to try it again. Please test it beforehand to save yourself some time!
It is also important to note that jailbreaking your iDevice may void its warranty so please proceed with caution and at your own risk. It is always a good idea to take a backup of your iDevice, refer to this post for more details.
Please note that these are some of the known bugs:
* Task switcher causes Springboard crash (temporary workaround is to use SBSettings process list)
* Bluetooth currently disabled due to sandbox problem
Check out if Cydia has saved iOS 4.2 beta 3 SHSH blobs, you may launch Cydia and wait to load the main page. You should see SHSH: 4.2b3 on the top of the page.