Many users faced problems in unlocking their iPhone 3G with firmware 3.1. In order to unlock your iPhone 3G through Ultrasn0w you should have baseband version 04.26.08. If you have baseband version 05.11.07 then you won't be able to unlock your iPhone 3G with firmware 3.1 as this version of baseband doesn't allow your iPhone 3G from getting unlocked via Ultrasn0w. Good news you can still unlock your iPhone 3G through Ultrasn0w but before that you have to downgrade your baseband firmware from 05.11.07 to 04.26.08.
- You must jailbreak your iPhone 3G running on firmware 3.1 before you may downgrade your baseband version from 05.11.07 to 04.26.08. Click here to jailbreak your iPhone 3G running on firmware 3.1
- After you have jailbroken your iPhone, Go to Cydia on your iPhone and Search for Fuzzyband and then install this application
- Start Fuzzyband app and touch on Downgrade button to downgrade your Baseband from 05.11.07 to 04.26.08
- Now you can easily unlock your iPhone through Ultrasn0w by following the instructions in the unlock guide here
NOTE: Downgrading of baseband will only work on phones that have the 05.08 (5.8) Bootloader from the factory. If you do not know your bootloader then you can run Fuzzyband and it will report the version number for you.