Untethered Jailbreak for iOS 4.2.1 for iPhone, iPod, and iPad!

The UNTETHERED JAILBREAK for iOS 4.2.1 has finally arrived! People can now have an untethered jailbreak for iOS 4.2.1!

WARNING: THOSE WHO NEED AN UNLOCK: DO NOT UPDATE TO A STOCK APPLE FIRMWARE… EVER. Use THIS GUIDE instead to show you how to jailbreak without updating your baseband!

If you do not need an unlock, please follow our step by step guide below:

1) Download iOS 4.2.1 for iPhone/iPod Touch. This jailbreak works for all iDevices

Image via Wikipedia

2) Download Greenpois0n to your computer (Currently Mac Only. Article will update when Windows is available)

(If the site is down, use THIS MIRROR <- This will likely work, but is not the most up to date version)

3) With your iDevice currently running iOS 4.2.1, connect it to iTunes

4) After your iPhone has been successfully backed up, keep it connected, and power it down. it’s time to run Greenpois0n.

5) The program will guide you through the steps on screen. Follow those step by step:

Press and hold the sleep button for 3 seconds

Continue holding sleep; press and hold home for 10 seconds.

Release sleep button; continue holding home for 15 seconds.

Now that your device is in full blown DFU, your device is now ready for jailbreak. Click on “Jailbreak” to inject the exploit.

A Video will be HERE (coming soon)

You’re going to notice a new icon on your home screen now. LOADER (green) will be there. use that to install Cydia. Afterwards, you’ll be prompted to remove it. Feel free to do so, as you no longer need this application anymore!

(Note: If for some reason you do not see the icon, just reboot your iDevice. It’s there now!)

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If you run into problems, try any of the updated pro-tips below:

Image representing iPhone as depicted in Crunc...

Image via CrunchBase

UPDATE: Dev Tip: If you’re stopped at “Greenpois0n initalized.” Re-try greenpois0n again, except when you’ve entered DFU mode, don’t let go of the home button. Also, Turn auto-sleep off, then launch Loader. (I had auto-sleep on and was 15% done, my iPhone feel asleep and now I have to start over).

Image via Wikipedia

HotTip: If you cannot get Cydia to install, run redsn0w and tell it to install Cydia (and nothing else)

UPDATE: Greenpois0n RC5_2 has been released to address the Greenpois0n initializing freeze mentioned above. You shouldn’t have to worry about that in the latest version.

How to: Untethered Jailbreak for iOS 4.2.1 for iPhone, iPod, and iPad! | HotTips!.