Just in a nick of time as iOS 4.3 is due out shortly, GreenPoisOn has released an untethered jailbreak for your iOS 4.2.1 iPhone. For all those new to jail breaking and the iPhone, be sure to check out our tutorial we just released on the basics. The Tutorial does not cover GreenPoisOn’s untethered jailbreak, but it is a great primer. I could not get on GreenPoisOn’s website but a lot of the comments on Engadget are saying that they were able to load Cydia as well. So it does appear that the untethered jailbreak does in fact work and that rebooting your device will not wipe out the jailbreak.
We still recommend that you hold off on this unless you absolutely know what you are doing. I have not gotten any feedback on the GreenPoisOn jailbreak from our developer friends, so in the mean time, it looks like we finally got a solution for all you iOS 4.2.1 users out there. Say it with me, FREEDOM!
Check out GreenPois0n for more information.