iPhone dev team has released iPhone 4.3.1 jailbreak for the iPhone. This jailbreak guide is compatible with iPhone 4 and iPhone 3GS running iOS 4.3.1 firmware.
First, download 4.3.1 firmware for your iPhone (links given below) and update your device using iTunes 10.2.1. Download Redsnow for iPhone and start the app. Browse for the iOS 4.3.1 file.
Click on next and select “install cydia”. Here, you may select any other option that you may like.
Now, you will need to turn off your iPhone and then plug it in into the computer before you press the “next” button.
Now, you will be told to put your iPhone into DFU mode. To do that – hold the power button for 1 second and then while holding it, press the home button as well. Then, after few seconds, while holding the home button, release the power button. Installation should begin now.
That is it. Wait for sometime while the Redsnow does the magic.
Note – RedSnow jailbreak is not for those iPhones that rely on carrier unlock.
Note 2 – iPhone 4.3.1 PwnageTool instructions are also available now.