The iPhone Dev-Team has ported Monte technique back to iOS 4.1 kernel (SHSH blobs) to achieve an untethered jailbreak for iOS 4.2.1 without having 4.2b3 SHSH blobs saved on Cydia. Redsn0w 0.9.7 update will untether iOS 4.2.1 jailbreak on S5L8930-based devices like iPad, iPhone 4, iPod touch 4G.
Previously to untether your jailbreak using Monte jailbreak method you needed to have the iOS 4.2b3 SHSH blobs saved on Cydia which was developer only and only those enrolled in the iPhone Developer program have legitimate access to that IPSW. Now you will only need your iOS 4.1 SHSH blobs. The team is also working on porting Monte forward to iOS 4.3, as confirmed via tweet.
Those who don’t know, Monte jailbreak technique is a backup solution being developed by iPhone Dev Team, because of stalled development for an “untethering” exploit for 4.2.1. Currently, it is Mac only but the next update might bring Windows support. There is actually a Windows version of redsn0w 0.9.7 beta6, but the team has not released as it is ”excruciatingly slow” as compared to the Mac version.
As of now, you can download Redsn0w 0.9.7b6 for Mac OS and use the tutorial guide (posted here) to jailbreak (untethered) your iPhone 4, iPod touch 4 or iPad running iOS 4.2.1. But, if you rely on the ultrasn0w carrier unlock, please do not use the beta version of Redsn0w. Interstingly, on the other hand, The Chronic Dev-Team is also re-packaging its Greenpois0n tool for an untetherd iOS 4.2.1 Jailbreak without requiring SHSH Blobs.
While we’re not sure about the exact status of final redsn0w 0.9.7 and Greenpois0n jailbreak, we do know that they are almost ready for release followed by iPhone 4 baseband 02.10.04 / 3.10.01 unlock. So, please be patient! For all future jailbreak and unlock software releases, please follow us on Twitter or become a Facebook fan.