The iPhone Dev Team have updated Redsn0w to work with the latest iPhone OS 4 beta4. This Redsn0w still works with the first beta, but doesn’t support betas 2 and 3. This is only for iPhone 3G. All the same warnings apply. This is not a working, day to day jailbreak, for the end user. This is meant for jailbreak developers to get their apps ready for the official iPhone OS 4 launch. Read this, before trying anything.

Another thing to remember is, this is not an unlock. iPhone OS 4 includes a baseband update that cannot be unlocked, so if you rely on your iPhone be unlocked, stay away from this.

It has been well documented that there are some unreleased exploits, that are being saved for after iPhone OS 4 is released, so we will get an official jailbreak for the next firmware. If your not a developer, you should avoid this, but if you’re brave, and have a spare iPhone, and want to try this out, you can download the new redsn0w here.