RedSn0w For 4.2.1 Firmware

• 1). Download the RedSn0w 0.9.6b4 software to your personal computer.
  
  
• 2). Turn your iPhone off and plug it into your personal computer using the iPhone USB cable.
  
  
• 3). Open the RedSn0w file to begin the process of jailbreaking your iPhone. Select the 4.2.1 firmware option. Click the "Next" button.
  
  
• 4). Click the check box next to "Install Cydia." Click the "Next" button. Click the "Next" button again.
  
  
• 5). Start your iPhone in DFU mode. Hold the "Power" button. While holding the "Power" button, press and hold the "Home" button. Release the "Power" button. Continue to hold the "Home" button until the installation begins.
  
  

GreenPois0n For 4.1 Firmware

• 1). Download GreenPois0n to your personal computer. Open the software when installation is complete.
  
  
• 2). Shut down your iPhone. Plug it in to you personal computer.
  
  
• 3). Press the "Prepare to jailbreak" button to begin.
  
  
• 4). Put your iPhone in DFU mode by following the on-screen instructions. You need to press the "Power" button for two seconds. Press the "Home" button while holding the "Power" button for 10 seconds. Release the "Power" button. Continue to hold the "Home" button until installation begins.
  
  
• 5). Click the "Jailbreak Now" button. Press the "Quit" button when your device is done with the jailbreak process.
  
  
• 6). Open the "Loader" application. Choose "Cydia" from the list of options. Click the option to "Install Cydia." Remove the "Loader" application when prompted.
  
  

Jailbreakme for 4.0.1 Firmware

• 1). Open the "Safari" application on your iPhone.
  
  
• 2). Go to the "Jailbreakme" website.
  
  
• 3). Move the slider to begin the jailbreak process. This process only takes a few minutes. Restart your iPhone when complete.