How To Jailbreak Your iOS 4.2.1 Device

Greenpois0n was released last week, finally bringing untethered jailbreaking to iOS 4.2.1 devices. The process is fairly easy, but there have been a few problems reported since the release so we’re going to walk you through a successful jailbreak step-by-step.

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The video above will show you how the whole process works, both on your computer and your iOS device, but here are the steps:

  • Connect your iOS device to your computer. It’s always good to back it up before jailbreaking in case something goes wrong, but before you get started with the jailbreak you’ll want to quit iTunes.
  • Download Greenpois0n and open it up. Press the jailbreak button as soon as you’re ready. Once the process starts, you’ll only have five seconds to get in position.
  • Hold down the sleep button at the top of your iOS device for three seconds.
  • Once the three seconds have passed, start holding down the home button without letting go of the sleep button. Do this for 10 seconds.
  • After the 10 seconds have passed, let go of the sleep button but continue holding down the home button for about another 10 seconds. Once the Greenpois0n logo appears in the window on your computer, you can let go.
  • Wait for the jailbreak to complete. It’ll finish on your computer first and the button that formerly read “Jailbreak!” will now read “Complete!” Click that to exit Greenpois0n. You can now disconnect your iOS device from your computer.
  • Your iOS device will take some time to boot. It might need to boot twice. Once it does, you should find a new application on your homescreen called “Loader”. Open that up, and if the jailbreak was 100 per cent successful you’ll see a single button that reads “Cydia”. Tap that and then tap the “Install Cydia” button that’ll pop up. This will — believe it or not — install Cydia on your iOS device. Once it’s done, you’ll have Cydia installed and your jailbreak is complete (although you may need to restart to see Cydia on your home screen).

If this doesn’t work for you and you don’t see Cydia, you’ll need to add the redsn0w jailbreak as well. You can download redsn0w here. You’ll also need the iOS 4.2.1 software for your specific device. Once you have both of these things you can run the redsn0w jailbreak on the device with the greenpois0n jailbreak already installed. Running redsn0w successfully should solve your Cydia problem if it occurs. I’ve jailbroken two 4.2.1 devices now and I’ve had the problem on only the second jailbreak, so this issue may have already been resolved.

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