iPhone Techie

Many of you asked me if there was / is a way to downgrade iPhones from 05.12.01 back to 05.11.07 or 04.26.08.

Well there is one way to downgrade your basebands but it only works for 3G iPhones, if you have a 3Gs iPhone and you have upgraded to the latest 3.1.3 Firmware through iTunes, then your basebands were upgraded as well and at this point there is nothing you can do to unlock your device.

The following instructions will only help you downgrade iPhone 3G which is currently on iPhone OS 3.1.3 with 05.12.01 baseband and older bootloader 05.08. This wont work with iPhone 3GS.

If your iPhone meets the above criteria, you can then use the latest version of Fuzzyband which supports iPhone 3.1.3 to downgrade your 05.12.01 baseband to the older 04.26.08 even if you accidently upgraded to the stock iPhone OS 3.1.3 from iTunes.

Once you have downgraded your baseband, you can then use ultrasn0w to unlock your iPhone on iPhone 3.1.3 firmware. Here’s how you do it.

Downgrading only works on phones that have the 05.08 (5.8) Bootloader from the factory. This is a very limited number of phones that were released in the first few weeks of the 3G production cycle. If you do not know your bootloader then you can run Fuzzyband and it will report the version number for you.

Step 1: To downgrade your baseband from 05.12.01 to 04.26.08, you must first jailbreak your iPhone 3G running firmware 3.1.3

Step 2: After you have jailbroken your iPhone, Go to “Cydia” on your iPhone and Search for “Fuzzyband” and then install this application.

Step 3: Start “Fuzzyband” app and touch on “Downgrade” button to downgrade your Baseband from 05.12.01 to 04.26.08.

Step 4: You should now be able to perfectly unlock your iPhone 3G using the latest version of ultrasn0w