It is sad that iPhone 4 baseband 4.11.08 / 4.12.01 owners have not found a reliable solution for a permanent factory unlock. The desired baseband to downgrade to is 01.59.00.

Downgrade iPhone 4 baseband

Since SAM unlock, Gevey, R-SIM, and Rebel Micro Pro can not unlock the baseband, it is similar to iPod Touch in functionality. We are still waiting for a genuine solution that will last forever.

Whoever says he has software unlock for 4.11.08 is not telling you the truth! We have news for those who have totally lost hope and thinking of getting another iPhone which is factory unlocked. There is a hardware hack which can downgrade 4.11.08 to 01.59.00 baseband and hence, you can use the latest version of ultrasn0w after the downgrade.

Infineon chip to downgrade 4.11.08 to 01.59.00 baseband
Infineon X 618 Baseband Chip

The method is provided by beijingiphonerepair and requires you to open up the iPhone, take out your logic board and sent it to them. The method is dependent upon chip replacement service.

The downgrading of iPhone 4 baseband 4.11.08 / 4.12.01 requires these components:

  1. Intel 36MY1EF 128MB NOR chip which costs US$67.00.
  2. Infineon Baseband Chip X618 (pre-programmed) baseband 1.59.00 which costs US$88.00.
  3. Worldwide standard shipping (can be tracked online and will take up to 20 days) which is free.
  4. China domestic first class express shipping which is free
  5. Labor charge which costs $24.00.
  6. 30-days warranty.

This is going to work but the main issue the workers at beijingiphonerepair face is sourcing those rare 1.59.00 baseband chips.

Downgrade iPhone 4 Baseband Warnings

  1. Only custom-made firmware should be used for upgrading while iTunes should be strictly avoided
  2. The IMEI serial number change will be caused by the change of the chip so the unlocked iPhone can be activated using any hacktivated custom firmware and latest ultrasn0w.
  3. There will be no issue in the process of restoration to stock firmware.

We know the method is hectic. But this hardware hack to downgrade iPhone 4 baseband 4.12.01 / 4.11.08 to 01.59.00 is reliable and can allow you to unlock iPhone using ultrasn0w.

Please feel free to share your thoughts!

  • Rom

    What’s a crazy about iPhone! Damn it, just changing to samsung! This is the way iPhone stock becomes suck! Just say good bye to an awesome phone! Such a crazy…

  • chan lee

    yes forget the iphone too much headache

  • letsee

    gonna bye samsung s3 1year passed stil no free unlock nd not available offcial unlok for canada hope nd nobody wrking on newer basebands. apple sucks

  • wannabee

    Because they got paid by Apple to gain more marketing sales of iPhone 4S. LOL!

  • Nima H

    Hi… First i have to apologize that my english is not well..!!
    I brought an i phone 4 unlocked from finland in carrier of sonera…. I had the same problem that all lock iphone owners have… But somthing strange happend .. When i was upgrading to ios 5.1 with itunes , cable dc ed and iphone stayed at recovery mode … I tried to get it out from recovery but it doesnt work… Finally i decided to make a custom firmware in 5.1.1 and with redsnow boot the phone… It worked and my iphone returned back to normal mode…but when i was in the procces of instalation .. It recognised sim card… It was unlocked.. Its base band was 5.11.08 before and after this proccess … What happend here? Im not a proffesional jailbreak man or sth like that … I just followed a way that linked in internet to get my phone back from recovery mode!!!

  • Jus Sayin

    Well Ur Luck Work3d that what happen3d 😛

  • thangculan

    Total cost for hardware hack above about US 180 ! Too expensive with the product you get back ! Old and not sure how long it can work after guaranty time limit !
    – You can buy one old iphone 4 BB 1.59.00 about 250 -350 depend capacity 16 0r 32 gb on the web in the US !
    – You got one block brand Apple in your home that you have to work hard to buy it before ! Let’s think about its and share with us your opinion .

  • iferg

    Waited 6 months for unlock ..gave up hope and just bought samsung galaxy s3 .after using it for 2 days I can’t believe I waited this long..goodbye apple you will never see another cent from me yourselves a favour and get rid of those stupid iphones won’t regret it

  • Maja Filova

    Finally, Unlock Sollutuion for my iPhone 4 baseband 4.11.08.

  • sbrennan

    how would swapping a logic board help at all? if you trade a locked logic board for another locked logic board how would that work?

  • Родион

    Четкий комент Колян)))

  • Pizza Guy

    in case you didn’t know, you can unlock your phone for 150 euros, which is about the same as chip replacement and you will have a neverlocked iphone, that’s that t-mobile germany does and from my sources, it’s one of the most expensive unlock methods from service providers

  • fari

    mooving to android aswel

  • Steps

    Just Free yourself by getting yourself a factory unlocked iphone, simple as ABCD and stop arguing ignorantly, u knew it was locked to a particular network before u went ahead to purchase it. if u want a hassle free iphone, why won’t u request for a factory unlock? after all, a factory unlock 4s costs almost same with Galaxy s3 besides ios is better than android and user experience is great. wise up.!!!!

  • Open iPhone?

    LOL !!!!!!!!!!!!!!!!!!!!!!

  • NiNe

    try restore with new sim!! some times that works

  • Goandroidgo

    Abandoned iPhones totally. Bought a samsung note, an s3, and a s4g instead.

  • Nomoreapplestuff

    Go Samsung go! Note. S3. iPhone? A joke.

  • nirav

    I accidentally update my baseband to 04.12.02 and its now cannot be
    used. Its already activated but I cant use any SIM card and its still
    shows “no service”. Does it mean I need to unlock it again? Please send
    me the details. TQ.

    IOS 5.1.1 (jailbroken)

    IMEI: 01 242100 132558 2

  • mandeep

    Someone here mentioned ios is a better experience than android?? dude ios isnt even half as good as android, plug and play file exchange, and application switching is a breeze. IPHONE is surely good phone but i had enough of their locking unlocking BS, and restrictions to use mp3 through itunes, basically android is do anything with the phone, and ios is just keep looking and dont try to customize thing.

  • Jhon

    In other words iPhone means iF**K Moving to Android 4.0 is great

  • abdul qadir

    please help me by giving the answer of my question?
    did iphone 4 baseband 0.12.01 cannot be downgrade without that hardware?

  • n

    i agree, such a crazy man..

  • BluntSmoke

    F&-at-k that, I like tinkering with stuff but I wouldn’t dream of trying this!!!

  • javed

    this is not a solution and i dont know what it is 🙁

  • Richter Bejay Maala

    how can i locked my iphone 4 4.12.05 firmware? thanks a lot..