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How to Downgrade iPhone 3.1.3 Baseband 05.12.01

iPhone's recent 3.1.3 firmware update hasn't really been a success for jailbreak users, quite a lot of issues have been reported while upgrading from firmware 3.1.2. Updating to OS 3.1.3 updates baseband of your iPhone as well, it will be 05.12.01. The latest Modem Firmware 05.12.01 baseband is not downgrade-able. So if you accidentally updated your iPhone to OS 3.1.3 and you want to downgrade/revert it back to OS 3.1.2, this guide will help you to do so. Please note that this tutorial is about downgrading iPhone 3G baseband which is currently on 3.1.3 firmware with 05.12.01 baseband and older bootloader 05.08 (5.8). This won't work with iPhone 3GS.

So if you have an iPhone 3G satisfying mentioned criteria then you can use the latest version of Fuzzyband iPhone app which supports iPhone 3.1.3 to downgrade your 05.12.01 baseband to the older 04.26.08 baseband. Please follow following procedure to do so.

Steps to Downgrade from iPhone 3.1.3 Baseband 05.12.01 to Older 04.26.08 Baseband

  1. You must jailbreak your iPhone 3G running on firmware 3.1.3 before you may downgrade your baseband version from 05.12.01 to 04.26.08. Please refer to following jailbreak your device: redsn0w 0.9.4, sn0wbreeze or PwnageTool 3.1.5.
  2. After you have jailbroken your iPhone, Go to Cydia on your iPhone and Search for Fuzzyband and then install this application
  3. Fuzzyband-1

  4. Start Fuzzyband app and touch on Downgrade button to downgrade your Baseband from 05.11.07 to 04.26.08
  5. Now you can easily unlock your iPhone through Ultrasn0w by following the instructions in the unlock guide posted here.

Please visit here and here respectively for complete coverage on jailbreaking and unlocking iPhone 3.1.3 firmware.

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    des11 years, 9 months ago


    Im a bit new to this but did managed to download my hacked (blackra1n) 3g to the old firmware3.1.2 after upgrading to 3.1.3 and loosing my hack.
    After i downgrade to 3.1.2 and rehacked(Blackra1n)i had no internet connection only wifi.
    On further investigation i noticed that my -general-network-cellular data network had vanished. Not just the network but all of the above?
    I have now updated again to 3.1.3 and have all back again.
    Any help would be most welcome.


    Binod11 years, 9 months ago

    I accidentally updated my iphone 3G and it is locked now.Iphone OS version is 3.1.2 and baseband version is 05.12.01

    Jose11 years, 9 months ago

    Sorry, but there is not going to be any way to downgrade it..

    Bj11 years, 9 months ago

    I have boat loader problem how to downgrade boat loader

    Please HELP

    Cyndrlla11 years, 10 months ago

    I finally got my iPhone 3GS downgraded to 3.1.2 with the baseband of 5.12.01 and after restore cydia is there again but it will not open. Any ideas as to what happened???

      manu11 years, 9 months ago

      wait, what? i thought this method only works on the 3G and NOT the 3GS!!