iPhone | How to Jailbreak Your iPhone 4 Using RedSn0w (Windows) [4.2.1]

[kalid660]

These are instructions on how to jailbreak your iPhone 4 on the 4.2.1 firmware using RedSn0w for Windows. The Mac version of this tutorial is here.
You will only be able to perform a tethered jailbreak at this time. This means you will need Redsn0w's assistance to boot into your jailbroken device. If you want to jailbreak a lower firmware version you can find the appropriate tutorial here.
Make sure not to update to iOS 4.2.1 if you need an unlock as one is not yet available!
Step One
Create a folder on your desktop called Pwnage
Download RedSn0w from here and place it in the Pwnage folder. Likewise, download the latest 4.2.1 firmware from below and place it in the same folder.
4.2.1 (4): iPhone3,1_4.2.1_8C148_Restore.ipsw
Extract the redsn0w executable from the RedSn0w zip file into the same folder.

Step Two
Connect your iPhone to the computer and launch iTunes.

Select your iPhone from the list of devices on the left. Now hold down Shift and click the Restore button. Restore is preferred as it won't create any wasted space on your iPhone.

1. Connect your phone with PC and switch off...
2. Open redsnow and choose Original firmware...
4. now click "Next"
5. Choose Only "Install Cydia"
6. now click "Next" again "Next" and follow the screen....
If you r getting White Cydia Icon just switch of your phone and open redsnow choose Stock firmware 4.2.1 and choose the option "Just boot tethered right now" and click "next" again "next" then follow the screen...then you will see the cydia...