Jailbreak iOS 4.2.1 for iPad, iPhone and iPod Touch using Redsn0w 0.9.6b4

By | November 23rd, 2010

The jailbreak tool for iOS 4.2.1 has finally been released that jailbreaks the latest firmware running on iPad, iPhone and iPod Touch (all devices) through redsn0w 0.9.6b4. The tool provides full support for Cydia and¬†MobileSubstrate¬†using the Geohot’s Limera1n exploit.

The earlier devices such as iPhone 3G, iPod Touch 2G (non-MC model) and iPhone 3GS (old bootroom) are untethered jailbroken. However the newer devices including iPhone 4, iPhone 3GS (new bootrom) and iPad will get a tethered jailbreak, meaning you need to connect the device to your computer on each restart.

The iPhone Dev Team has ensured that Comex is working on an exploit that will make all the devices untethered jailbreakable on iOS 4.2.1. Though if you don’t need to restart your device often, you can safely proceed here.

Warning: This procedure will update your baseband. Thus if you rely on an unlock, stay very away as it might lock your device, possibly forever.

Follow to guide below to proceed with this method. It is advised to read the whole procedure before starting.


  • Download Redsn0w 0.9.6b4. ¬†[Windows] [Mac]
  • Download iOS 4.2.1 compatible for your device. You can select and download the firmware from here. Now update your device to the latest firmware using iTunes 10.1.
  • Run the Redsn0w 0.9.6 beta4 and browse it to the downloaded IPSW file. Once the file is verified, proceed to the next step. Select “Install Cydia” option and proceed to the next window. You may select “Enable Battery Percentage”, “Enable Wallpapers” and “Enable Multitasking” if your device doesn’t support it natively.

  • Now plug off your device while it is plugged it and follow the on-screen instructions to enter into the DFU Mode. The setup will guide you in this procedure. If you could’t enter DFU mode, youtube it to see a guided video.

  • Once the setup recognizes the DFU mode, it will start the jailbreak. Now sit back and relax while your device is pwned. You should see Cydia installed on the next reboot (this will take a few minutes)

The procedure is very simple, though if you encounters any errors, please mention here so we can provide the guide.