Musclenerd the member of iPhone Dev-Team, just tweeted few minutes ago that they sucssfully ported “monte” technique back to iOS 4.1. This technique will allow users to untether the iOS 4.2.1 jailbreak on iPhone, iPad, and iPod touch without needing 4.2b3 SHSH blobs.
Ported Monte back to 4.1 kernel (SHSH blobs). Next step: porting it forward to 4.3beta!
Think of Monte as a “green” jailbreak. It recycles (for example) 4.1’s exact JB exploit on 4.2.1 Waste no exploits.
As they recently announced that the new version of Redsn0w 0.9.7 will works on both Windows & Mac, and now they are working to port iOS 4.3 in finall version. So, now you will be able to untether your iOS 4.2.1 jailbreak using iOS 4.1 IPSW files.