redsn0w is a tool for Mac and Windows that provides untethered jailbreaks for iOS versions including:

  • iPhone 4S: 5.0, 5.0.1, and 5.1.1
  • iPhone 4 (GSM): 4.1 through 4.2.1; 4.3.1 through 4.3.3; 5.0.1 and 5.1.1
  • iPhone 4 (CDMA): 4.2.8, 5.0.1, and 5.1.1
  • iPhone 3GS: 4.1 through 4.2.1; 4.3.1 through 4.3.3; 5.0.1 and 5.1.1 (old-bootrom iPhone 3GS is untethered on all versions)
  • iPhone 3G: 4.1 through 4.2.1
  • iPad 3rd generation: 5.1.1
  • iPad 2: 5.0.1 and 5.1.1
  • iPad 1: 4.3.1 through 4.3.3; 5.0.1 and 5.1.1
  • iPod touch 3rd generation and 4th generation: 4.1 through 4.2.1; 4.3.1 through 4.3.3; 5.0.1 and 5.1.1
  • iPod touch 2nd generation (which includes devices sold as iPod touch 3rd generation 8 GB): 4.1 through 4.2.1

And tethered jailbreaks for iOS versions including:

  • iPhone 4 (GSM): 4.3.4 through 5.0, 5.1, and 6.0 through 6.0.1
  • iPhone 4 (CDMA): 4.2.9 through 5.0, 5.1, and 6.0 through 6.0.1
  • iPhone 3GS: 4.3.4 through 5.0, 5.1, and 6.0 through 6.0.1
  • iPad 1: 4.3.4 through 5.0, and 5.1
  • iPod touch 3rd generation: 4.3.4 through 5.0, and 5.1
  • iPod touch 4th generation: 4.3.4 through 5.0, 5.1, and 6.0 through 6.0.1

redsn0w runs on already-upgraded un-jailbroken devices.

Steps: Download redsn0w for Mac or Windows. Open it, plug your device into your computer, and follow redsn0w's instructions.

If your version of iOS has a tethered jailbreak, this means you need to plug your device into a computer and run redsn0w every time your device boots (such as when it runs out of battery), or else it may get stuck at the Apple logo while booting — or it may boot up but in a seemingly "unjailbroken" state where Cydia and Safari will crash when you try to open them. To boot tethered: open redsn0w, click "Extras" and then click "Just Boot".

Tips for Windows users: Extract redsn0w.exe to your desktop instead of running it from inside the .zip archive. You may need to right-click redsn0w to run it from an administrator account and/or run it in XP compatibility mode. If you use Internet Explorer to download an IPSW file, you may need to change the file extension from .zip to .ipsw in order to use it.

Note for unlockers: if you upgrade iOS using iTunes, it will upgrade your iPhone's baseband, which negatively affects iPhones unofficially unlocked with ultrasn0w. Instead use redsn0w's "Custom IPSW" feature to upgrade and jailbreak your device while preserving your baseband. (Not currently possible on iPhone 4S.)