- Download firmare 3.0 from here:
http://appldnld.apple.com.edgesuite.net/content.info.apple.com/iPhone/061-6578.20090617.VfgtU/iPhone1,2_3.0_7A341_Restore.ipsw- Upgrade your iPhone 3g to firmware 3.0 in iTunes. Do this by going to iTunes and clicking the update button in iTunes after connecting your iPhone to the PC with the USB cable.
- Download the RedSn0w software for windows from the DevTeam website:
http://blog.iphone-dev.org/post/126908912/redsn0w-in-june- Unzip and run RedSn0w
- Click “browse” and select the firmware you downloaded: "iPhone1,2_3.0_7A341_Restore.ipsw"
- Click “next”
- Keep “install Cydia” selected and click “next”.
- Make sure your iPhone is plugged into the computer and that it is
OFF.
- Click “next”.
- Follow the instructions to put your iPhone into DFU mode.
- The iPhone should reboot now and the jailbreak process should start.
- A message saying that it is “done!” will be displayed and that means it is finished :) You should be a Cydia icon on your home screen :)