These are instructions on how to jailbreak your iPhone 3GS and iPhone 4 using Greenpois0n for Windows. Greenpois0n supports the iOS 4.1 and iOS 4.2.1 firmware. Use Limerain if you want to jailbreak iOS 4.0, iOS 4.0.1, iOS 4.0.2. Do not update to iOS 4.2.1 if you need the Ultrasn0w unlock. Ultrasn0w does not support that baseband yet. The only exception is the iPhone 4. You can update to iOS 4.2.1 without upgrading your baseband by following this tutorial.





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 (Windows) [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.


Download greenpois0n rc5 For Windows

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 Prepare to Jailbreak (DFU) 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 Quit 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.