The fourth beta redsn0w 0.9.7b4 is out for download for iOS 4.2.1 jailbreak which no longer requires you to install and run a separate program for the usbmux. In addition to thisredsn0w 0.9.7b4 brings fix to race condition in the GUI that was causing redsn0w to crash during the “Preparing JB Monte Files” step. iPhone Dev Team is still ironing out bugs in and Skype that is still lurking the final release of redsn0w 0.9.7.
It requires access to the iOS 4.2b3 firmware and your iOS 4.2b3 SHSH blobs saved. If yourely on the ultrasn0w carrier unlock, please do not use this updated redsn0w tool. Currently, the untether is Mac only but the next update will bring Windows support. Download the Redsn0w 0.9.7b4 for Mac OS now and use the tutorial guide to untether jailbreak 4, iPod touch 4 or iPad running iOS 4.2.1. If your device is currently jailbroken with one of the previous betas, please do a fresh restore first.