Just about an hour ago greenpois0n RC5 was released, and with this release comes a fully untethered iOS4.2.1 jailbreak. This iOS 4.2.1 untethered jailbreak is stable, does not require the iOS 4.2 Beta 3 SHSH blobs, and ONLY works with the Mac OSX operating system. For Windows, support will be coming soon, so don’t worry. Read the tutorial below to untether jailbreak your iDevice running iOS 4.2.1 with greenpois0n RC5 jailbreak tool.




As I am sure you already know, using tools like greenpois0n RC5 and Limera1n are extremely easy to use. In fact they are so easy that a tutorial is not generally needed. Regardless of this, I am still going to provide you with a tutorial on using greenpoison RC5 to untether jailbreak the iOS4.2.1 firmware. As there are actually a couple of things you should know before jailbreaking your iDevice with greenpois0n RC5.


greenpois0n RC5 Supports :

* iPhone 4
* iPhone 3GS
* iPad
* iPod Touch 2G
* iPod Touch 3G
* iPod Touch 4G


Before using greenpois0n RC5 jailbreak, read these points below : 

* You must have a clean install of the iOS 4.2.1 Firmware (Yes, this means restoring).
* greenpois0n RC5 does not hacktivate your iPhone.
* greenpois0n RC5 supports MAC OS X only (Windows support coming soon).


Jailbreak iOS 4.2.1 With greenpois0n RC5 [How To] :

1) The first thing you are going to need to do is ensure your iDevice is running the iOS 4.2.1 firmware. This is the only firmware version that greenpois0n RC5 supports.

2) Once you are running a clean install of the iOS 4.2.1 firmware, download greenpois0n RC5 jailbreak tool. You can do this by clicking the direct download link here.

3) Double click the downloaded greenpois0n-osx_rc5.zip file to extract the archive then double click greenpois0n from the desktop to launch the application.


4) Connect your iPhone to the computer, power it off, then click the large Jailbreak button.

You will now be instructed on how to place your iPhone into DFU mode :

* You will be asked to press and hold the sleep button for 3 seconds.

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

* Release sleep button, continue holding the home button. Do not release the Home button at this point.



5) Once your iPhone is successfully in DFU mode, greenpois0n RC5 will begin the jailbreak process.

6) Once greenpois0n RC5 informs you that it has completed you can release the Home button. Click the Complete button to close greenpois0n RC5.

7) Now you will notice some verbose mode text scrolling on your iPhone. After the iPhone restarts you'll notice a new Loader application on your Springboard. Press to launch it.



8) Press to select Cydia then press the Install Cydia button.



9) Once Cydia has been installed successfully you can remove Loader by pressing the Options button then press the Remove Loader.app button.



10) Restart your iPhone then run Cydia. Let it do all the necessary updates then follow our Unlock tutorial if required for your iPhone here.

If you are facing any errors using greenpois0n rc5, follow this guide.

Hopefully this tutorial helped you jailbreak your iOS 4.2.1 iDevice untethered with greenpois0n RC5. Let us know if you need any help, or run into any errors, we would be more than glad to help