(Not for iPhone 4S, iPad 2, or iPad 3)
Step 1: Download the latest version of the iPhone Dev Team’s Redsn0w tool for your operating system (Windows / Mac).
Step 2: Not a requirement, but it is always good
practice to connect the device to iTunes and perform a backup of the
contents. Alternatively, users can opt to back up the device to iCloud
if enabled.
Step 3: After the backup is complete, upgrade the
device’s firmware to iOS 5.1.1. Users can choose to either do this via
an OTA update on the device, or by plugging the device onto your PC or
Mac, firing up iTunes and accepting and installing the update, or by
downloading the iOS 5.1.1 device-specific firmware file and doing a
manual install through iTunes.
Step 4: Download the iOS 5.1 (not iOS 5.1.1) IPSW file that corresponds to the specific device you are using.
Step 5: Locate the Redsn0w download folder from Step 1, unzip the contents and run the executable file to launch Redsn0w.
Step 6: Select ‘Extras’ on the Redsn0w GUI and the choose the ‘Select IPSW’ option.
Step 7: When prompted, point to IPSW file from Step 4 (which is iOS 5.1) and select it.
Step 8: On the main home screen of Redsn0w, select
‘Jailbreak’ and then make sure the ‘Install Cydia’ option is selected
before proceeding.
Step 9: The on-screen prompts will now walk you through the process to put the device into DFU mode. This is a requirement for the jailbreak process to be successful. Make sure to follow all steps carefully.
Step 10: When DFU mode is detected, Redsn0w will
automate the rest of the process on-screen before finishing off on the
device. During the process, it is entirely normal to see white lines of
text scrolling down the device’s screen. When the device reboots, the
jailbreak process is complete which should be evident by the presence of
the Cydia icon on the home screen.
Since this is a tethered jailbreak, you will have to boot your device
into tethered boot mode on every restart. You can do this by launching
Redsn0w, select "Extras", then"Just Boot" in order to boot your device
tethered.