: Download PwnageTool 4.2 here
. Also Download the appropriate 4.2.1 firmware bundle (available from Apple
). For the walkthrough I used an AT&T iPhone 4.
: Open PwnageTool and click 'Expert Mode' at the top, then click the device you'd like to jailbreak.
: Click "Browse for IPSW and browse for the firmware bundle you downloaded (should be firmware 4.2.1)
: Click 'General' and select functions as needed.