You can find the Mac version of this tutorial here. If you have an iPhone 3G click here, if you have and iPhone 3GS click here
Create a folder called Pwnage on your desktop.
Download the following files and place them in the Pwnage folder you just created:
- BL 3.9
- BL 4.6
- 3.1.3 (2G): iPhone1,1_3.1.3_7E18_Restore.ipsw
Extract the RedSn0w application from the zip file to the Pwnage folder.
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.
Navigate to the Pwnage folder on your desktop and select the firmware ipsw. Click the Open button to continue.
Once iTunes has finished updating your iPhone to the desired firmware you may launch redsnw0w.exe from the Pwnage folder on your desktop.
Once RedSn0w opens click the Browse button
Select the firmware ipsw we placed in the Pwnage folder on our desktop then click Open
Once the firmware has been verified click the Next button to continue.
From this window you can select the jailbreak options you would like. If you have already pwned your device check the Already pwned option.
Verbose boot displays detailed information on boot of your device and is generally only needed by developers and advanced users.
Make sure the Cydia and Unlock options are selected. For this tutorial we will also select Custom boot logo and Custom recovery logo.
When you click to select each custom logo option a dialog window will appear asking you to select the image. Locate the image you would like to use then press the Open button.
*Remember the rules for boot logos are: RGB or Grayscale format with Alpha channel and dimension below 320x480. If you would like to use the iClarified ones they can be found here: Boot Logo, Recovery Logo
Click the Next button to continue
We will know need to set the location of our bootloader files.
Click Browse and select the 3.9 bootloader file from the Pwnage folder on your desktop.
Click Browse and select the 4.6 bootloader file from the Pwnage folder on your desktop.
Click the Next button to continue.
Please plug your iPhone into the computer and make sure its OFF then click the Next button
RedSn0w will now guide you through the steps to get into DFU mode.
Hold down both the Home button and the Power button for 10 seconds.
Release the Power button and continue holding the Home button until RedSn0w detects the device.
Your iPhone will now reboot
RedSn0w will then begin uploading the new RAM Disk and Kernel.
Once this is complete you will be notified that RedSn0w is done. Click the Finish button. After your iPhone reboots (5 minutes or so), it will run BootNeuter then be unlocked and jailbroken with Cydia on the SpringBoard.
*As usual a big thanks to the iPhone Dev-Team for this contribution to the community.