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iPhone Dev Team had released Redsn0w 0.9.7b1 that implements the “backup plan” for iOS 4.2.1 untethered jailbreak for iPhone 4, iPad and iPod touch 4G.
It was meant only for beta testers and not for the general public as there are still some known issues that need to be addressed. However, users who tried the beta version reported a number of issues. Dev Team has promptly released a new version of Redsn0w to address some of the issues.
Beta testers reported a number of issues such as: