The Dev-Team has just released a fresh beta version of redsn0w, version 0.9.6b1, which allows users to jailbreak the iPhone3G and iPod Touch 2G on iOS 4.1 or 4.0.
The tool uses the same pwnage2 DFU-mode exploit that we’ve all been using with redsn0w since the 2.x days. There is nothing new for Apple to patch from this update, it's simply still compatible.
For those that are getting excited, settle down: this does not include the SHAtter exploit that has been on everyones mind lately.
IF YOU USE THE ULTRASN0W UNLOCK, PLEASE WAIT FOR PWNAGETOOL TO SUPPORT 4.1. DO NOT USE REDSN0W. That’s because to use redsn0w at 4.1, you need to already have updated to official 4.1 from Apple. If you do that, you lose the ultrasn0w unlock (possible forever).
Note: if you have an “MC” model of the ipt2g, your jailbreak will be tethered…sorry! (Consider rolling back to a FW supported by jailbreakme.com or spiritjb.com)