This guide will show you how to jailbreak your iPhone 3GS 3.1 by updating from firmware 3.0/3.0.1 through iTunes with 3.1 custom firmware created using pwnagetool 3.1.3. Please note that your iPhone 3GS must be jailbroken or pwned. If not, jailbreak it first using this guide.
Jailbreaking iPhone 3GS Steps:
- Update your iTunes to latest version
- Download 3.1 custom firmware for non-official carrier user here
- Restore your iPhone 3GS using iTunes with the downloaded custom firmware
- For official carrier user, you need to activate your iPhone 3GS through iTunes
- For non-official carrier user, you need unlock your iPhone 3GS with the ultrasn0w