How to jailbreak iOS 4.2.1 all iDevices: iPhone 4/3GS/3G, iPod Touch, iPad & Apple TV

This will guide you on using greenpois0n RC6.1 to jailbreak your iDevice with iOS 4.2.1:

• iPhone 4
• iPhone 3GS
• iPod touch 4G
• iPod touch 3G
• iPad

• For Mac
• For PC (Windows)

1. Plug your iDevice to your computer
2. Open iTunes & prepare to put your iDevice to DFU mode
3. DFU Mode: Press and hold both POWER and HOME buttons for EXACTLY 10 seconds
4. DFU Mode: Release the POWER button but keep holding the HOME button for another 15 to 20 seconds
5. You can release the HOME button once your computer beeps like a USB device has been connected OR once iTunes alerts you that it has detected an iDevice in recovery mode, which looks like this:Click on image to view larger.
6. Close iTunes
7. Open greenpois0n
8. Click NO when it asked you if you'll be jailbreaking an Apple TV
9. Click Jailbreak Note that you don't have to follow the DFU directions anymore because you did it already in steps 3 to 5 (read again if necessary)