Jailbreak iOS 4.2.1- Every iPhone, iPod Touch & iPad – Redsn0w

This is how to Jailbreak ALL iDevice on 4.2.1! Although the new devices are semi-tethered! **NOTE** Redsn0w 0.9.6 b6 is the newest version! I STRONGLY Recommend Using That One! DON’T ATTEMPT IF YOU RELY ON A CARRIER UNLOCK! For iPhone 4, 3GS (New Bootrom), iPod touch 4G / 3G / 2G, iPad ONLY: Now from here onwards, whenever you want to do anything related to jailbreak like SSHing into your device, or running Cydia, you must first run your device in the so called “jailbroken state” on every reboot by using “Just boot tethered right now” option in Redsn0w. Steps:
1. DOWNLOAD ALL FILES LISTED IN THE DOWNLOAD SECTION BELOW! (Right click Redsn0w and set compatibility to windows xp (service pack 2) if your on Windows 7 or Windows Vista and run as administrator)
2. Plug in iDevice and THEN TURN IT OFF – Run Redsn0w
3. Browse for the firmware you downloaded from the link below and select it
4. Hit next and then check install Cydia and all other options you want to apply (DON’T check Install custom bundle, Just boot tethered right now OR Just enter pwned DFU mode right now)
5. Hit next and follow the on screen instructions, they are as follows: a. Hold down the power button for 3 seconds b. Continue holding the power button and start holding the home button and continue HOLDING BOTH for 10 seconds c. Let go of power and continue holding home button for 20 seconds (even after it skips to the next screen! YOU MUST COUNT TO 20 ON YOUR OWN)
6. Wait for it to finish and reboot.