The dev-team has just released Redsn0w 0.9.7b6 to untehtered jailbreak for iOS 4.2.1, the new beta has successfully fixed the Skype crashes, now it seems that now the redsn0w 0.9.7 is free of bugs.
The sixth beta is now available (testers ONLY please!). This version fixes Skype. Please do not pirate the 4.2b3 IPSW! Only those enrolled in the iPhone Developer program have legitimate access to that IPSW using these links (http://pastie.org/1403214) (the links won’t work unless you’re a legit developer currently logged in).On the above quoted text section, dev-team confirmed that the next step is porting Monte which means that you will not be in need of 4.2b3 SHSH blobs to untethered your jailbreak on iOS 4.2.1 and to make the Windows version less painfully slow.
Unlike the last few betas, you can freely run beta6 over beta5 without a problem (but for testing purposes, we’d really like people to try both ways….from stock, and from already jailbroken).
Now that the sandbox, Bluetooth, and Skype issues are fixed, our next priority is porting Monte back to 4.1. We’ll also try to make the Windows version less painfully slow.
To use Redsn0w 0.9.7b6, use our guide posted here while removing usbmuxd steps since it doesn't required usbmuxd anymore.
Download iOS 4.2.1 for iPhone 4, 3GS, 3G, iPad, iPod touch
Download Redsn0w 0.9.7b6 for Mac
Download iTunes 10.1.1 for Mac and Windows