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IMEI Unlock: Downgrade iPhone 3Gs baseband to 5.13.04 from 6.15.00

Over the years, I bought many iPhones for family and friends from US. Only for the last 2 Years, Apple has been selling unlocked phones. Before that, for most phones, I had to figure out a way to jailbreak and carrier unlock the phone via Ultrasn0w.

For iPhone 3Gs, to carrier unlock your phone, I had to upgrade my phone’s baseband to 6.15.00 (iPad’s baseband) and then using Ultrasn0w I could use the phone with any service provider in India.

However for iPhone 4 with baseband 4.11.08, Ultrasn0w could not do the carrier unlock. Basically there was no way to upgrade/downgrade the baseband. I had given up hope and my daughter was happily using those iPhones as toys. Just then I came across BejingPhoneRepair’s IMEI Unlocking Steps. I was very skeptical that this would work. Paid $15 USD for 1 phone and it worked like a charm. I was able to unlock all my iPhone4’s.

Then I had this iPhone 3Gs, which I had jail broken and upgraded the baseband to 6.15.00. I wanted to upgrade that to iOS 6.0.1. So I thought I might as well use the same IMEI unlock. After I paid and followed the exact same steps I did for iPhone4, I realized there was an issue:

It refused to recognize the SIM card. Then I came across this article from Richard Ker of BeijingiPhoneRepair. This explains that iTunes does not let you activate your iPhone 3Gs with baseband 6.15.00 on iOS 6.

The solution they propose is to downgrade your baseband to 5.13.04 first. To downgrade your baseband you can get the original iPhone 3GS iOS 5.1.1 firmware and then using Redsn0w to flash the baseband. Since I already had iOS 6.0.1 installed on my phone, I kept getting the following error:

AppleBaseband: Could not find mux function error.

Tried downgrading my phone to iOS 5.1.1 using Redsn0w and iTunes, but no luck. Apple does not allow you to  downgrade from iOS 6 to iOS 5. You need the SHSH blobs saved for iOS 5.1.1 to downgrade as Apple has stopped signing this firmware. Using Redsn0w I tried searching Cydia’s server to see if SHSH blobs were available. No luck. So I followed the following steps to fix the issue:

  1. Using Redsn0w (0.9.14b2 or above), I put my phone in DFU mode.
  2. During the restore process, iTunes verifies with Apple’s server if the device is allowed to install the specific version of firmware. To work around this issue, I appended the following line to my host file (/etc/hosts) to fool iTunes.
  3. Then using iTunes, restored iOS 4.1 (8B117) firmware on my phone. I usually download my firmwares from iClarified’s site.
  4. After Launching redsn0w. Under Extras > Select IPSW and select the original iOS 4.1 (8B117) firmware
  5. Did a controlled shutdown of my iPhone (“slide to power off”).
  6. Returned to the first screen and clicked ‘Jailbreak’.
  7. Checked the ‘Downgrade from iPad baseband’ checkbox and unchecked Cydia. Next.
  8. Redsn0w started the downgrade process and you finally I saw the ‘Flashing Baseband’ screen on my iPhone with the Pawnapple icon. DO NOT INTERRUPT your iPhone while baseband flashing is in progress. This steps takes a good 5-10 mins.
  9. When this was done, after rebooting my iPhone, the baseband was downgraded to 5.13.04.
  10. Then I connected my phone to iTunes once more and upgraded my firmware to iOS 6.0.1.
  11. Once the upgrade was done, I saw this screen on iTunes.
  12. Now my phone can connect to the local service provider.
    Working iPhone with 6.0.1
  • user…

    is it possible to download any 4.1.1 sw and try yours procedure

    • I’m sorry, I’not sure. I’ve only tried it with 4.1 (8B117)

      • 3gstucked

        To what I have understood, the problem is being caused because you are activating with BB 6.15.00 AFTER ios 6 release date and its not because you are using ios 6 ( though most people have upgraded to ios 6 & think its because of ios 6, but its only because of the date i.e. if you upgraded to 5.1.1 with BB 6.15.00, you still would have stucked with the no sim!)

        I am saying this because I got the same error after I downgraded to ios 4.1 BB 6.15.00 after ios 6 release date and I wasn’t able to activate my iphone.

        Hopefull I downgraded with redsn0w so the matter is resolved now.

        So if you still have the problem when you ios is not ios 6.xx, have in mind that its because of the release date, and you just have to downgrade the BB either way, I mean downgrading the ios won’t do the work since you are actvating a device with 6.15.00 BB after the release of ios

  • Nate

    Awesome instructions! I had this exact problem and thanks to the miracle of the interweb, found this blog post. Thanks a ton for posting this.

    • max

      how did u make it??im not knowing how to solve…I have the same problem of no carrier detected/

  • RT

    OMG! I’m glad I found your post. THANK YOU SO MUCH!!!

  • kerol

    after you upgrade to ios 6.0.1 using itunes, is it your phone still jailbreak or not?

    • No its not jail-broken. In the past, the only reason I had to jailbreak my phone was to enable carrier unlock. Now with the IMEI unlock, I don’t need to jailbreak any more. This allows me to freely upgrade to new version of iOSx without having to worry about a thing.

  • Pradeep

    hi naresh can you pleas help me with steps 11 onwards..i am bit hesitant to restore without using redsnow , since baseband might change to 6.15.00 again..!

    • You don’t have to worry, the baseband won’t change. I’ve tried it at least on couple of phones and found it consistent.

  • Kathir


    At step 7, it shows the connected device doesn’t support untethered error message redsn0w_win_0.9.15b3. Please help me.

    • I’m sorry I’ve not seen that message before. If you provide me some more details, I might be able to help.

      • Hey I’m having the same issue, there isn’t much more information to provide, that was the only error that shows up on redsnow. I just set up a tethered boot and see if I can go from there, i’ll let u know if it works. otherwise please advise on what that issue may be

      • I just did the boot tethered option, then disconnected, restarted, reconnected and opened redsnow, went to jailbreak again and followed the steps as normal and it’s working!

  • LKrey

    Hi Naresh! On step 2 you say you appended the line to your host file (/etc/hosts) to fool iTunes. How do you even do that especially during the restore process? Then the next step (step 3) on restoring iOS 4.1 firmware on iTunes, how do I go about it? Could you give explicit step by step details? Next, under Redsn0w, where do you get the iOS 4.1 from, to select from the IPSW? And last but not least, last time I used Redsn0w and like you, it didn’t work due to the baseband, and I clicked on Jailbreak, there was no option to Check the ‘Downgrade from iPad baseband’ checkbox and uncheck Cydia. But I guess I can cross that bridge when I get there. Right now I need to get the iOs4.1 and all of that. Can you help me please? I work overseas and my phone does not work here, only in the US. I already unlocked it, upgraded it to 6.01, managed to activate it but the local SIM card does not work. I think your solution is the rigth one but I need a step by step outline of how to go about it. Your help is much appreciated.

  • maeee

    Thanks so much! This really helped. bought a factory unlock for my sisters iphone 3gs which was her Christmas present and it was on the old 4.2.1 (bleeech) so I flet horrible and figured id give buying a factory unlock code a try. then I ran into the phone being unable to activate due to the old ipad baseband and I had no clue how to downgrade. This is the perfect way to show step by step how to do this. thank you!

  • LKrey

    Thank you! You’re the best! I’ll get on it today and let you know. Huge thanks for answering and addressing my concerns. Keep the great work, really!

  • goodjob

    Hi man, it’s genius. followed the steps until step 10. Until step 9, everything was fine. but, upgrading back to ios 6 led me back to the first problem I came here for. Now, I am trying to follow the steps until step 9 all over again. could you please explain the last steps , ios 6 parts in case I missed something? thanks

    • These are the steps, nothing I’ve missed. Others are able to fix their phones. Please try again and see if it works.

  • taha

    does it hv to do wid new bootrom n old bootrom????i hv n iphone 3gs (IMEI Number : 012163004228112
    Serial Number : 880169593NQ),bcz on sm syt i had seen tat if its a new bootrom,phone myt gt bricked?????

    • Please check others comments, few other people have fixed their phones with old bootrom.

  • InLaymansTerm

    Please, I would really appreciate some help, I have an iPhone 3GS 4.0, old bootrom ; BB is 05.13.04. It’s jailbroken and unlocked. I have saved SHSH blob 5.1.1 locally. Naresh Please help show me the process and tools how to upgrade to 5.1.1 without upgrading the baseband.

    Is this possible? And if it is, will the iphone still jailbroken and unlocked once upgraded to 5.1.1? Thanks man.

    • Eduardo

      Hi! Looking about what you have, apears to me very simple to put your phone regular and without any stress.
      Lets talk? ehoff at

  • was

    i need SHSH blob 5.1.1 please help !!!

    • You actually don’t need the SHSH blob, these steps works fine without it.

  • Kevin Estrada

    Hi naresh, i found this and quite useful. I was wondering if this is the real IMEI unlock because this is what i am looking for. Do I have to follow the steps? My 3gs is at 4.1 with 6.15 BB. If i followed the steps above will it become unlock at ios 6.0.1/6.1? Thank yoy

    • If you are already at 4.1, then you can upgrade to 6.1 starting with step No. 6. Yes this is a real IMEI unlock.

  • MellieMelJ

    I was stuck for two days on the activation screen, repeat 3194 errors in Itunes and NO carrier signal (BB 6.15 and IOS6) and followed your tut exactly and I now having a working 3gs (with activated att sim) running BB 5.13 and IOS6! Thank You, thank you!!!

  • Savar

    Hi Naresh-

    I also have a 3gs which was unlocked for me in the US, specifically to travel in India. I’m in India now, and it is working fine with the local carrier, but Itunes won’t recognize the phone. I Have IOS 4.3.3 (8J2) installed, with baseband 6.15.00. It’s not imperative for me to have the latest IOS, but it would be good to be able to transfer my music, upgrade apps etc.

    Is there a simple way to upgrade with this config? Or at least get itunes on board?

    thanks for all your help-

    • Not sure why iTunes won’t recognize your phone. Have you tried connecting with another iTunes to check if its an issue with the phone or your iTunes is acting up.

      I would recommend, upgrading to the latest version of iOS, other than cool new features, they do fix a lot of security issues with the phone.

  • rick

    excellent tutorial. I should have followed your steps from the beginning. I wasted hours for nothing. thank you very much

  • harra

    thanks after 3 days of trying to jailbreak and unlock and this took half an hour thanks again ya a diamond

  • Mario

    Thank you so much!! This tutorial was brilliant!

  • Luis

    Thank you, works after fail update to 6.1 and 6.15 baseband, I got error 1015, but a video on youtube “How To Fix Error 1015 on ALL iPhones and iTouches” got me going.

  • Cesar

    excellent! at first was a little hard to understand but at the end result was great! the iphone 3gs now is working thank you

  • dwendigirl

    you are a GENIUS — thank you for sharing this information.

  • etienne

    Great,it finally worked for me and i can use again my old 3gs .thanks man,you are the best…

  • Thanks, man! it helps!

  • iphone

    hi naresh,
    Wat do u mean by fooling itunes, i dint get u…..could you explain???
    and i have downloaded firmware 5.1.1 so while downgrading redsnow shows failed error

    • During the installation process, iTunes checks with Apple’s server to find out if it can allow the older version of the firmware to be installed on the phone. Apple obviously does not want iTunes to install the old version. To avoid this issue, we set a different IP address for Apple’s server and this way the fake Apple Sever will allow iTunes to install the old firmware. – That’s step number 2 in my instructions.

      What error did redsnow show?

    • kornel

      For the people who wants to unlock ATT phones, go google attiphoneunlocking, they unlock any model and firmware up to date.

      • dominik90

        Tried some sites, unlockingcell com is slow and crappy shit, didn’t actually unlock my phone. attiphoneunlocking com is worth the money and way faster, didn’t believe they really did it in 2 hours. factoryunlockpro info is also shit.

        • george

          5 dollar sites are all SCAM, waste of money and time

  • Luis M.

    what version of redsn0w were you using?

  • i have problem with step 8.proces stop at fetching baseband files(please be patient).

    • Yes sometimes it takes a long time depending on your internet connection speed.

  • DeeBee

    It works, at first i did not believed it. but now…but you have to make sure, which bootroom your iphone has. for this identification just download snowbreed, which can easily identify the bootroom. after that run redsnow and there answer the question if your iphone has a new or old bootroom.

  • Rado

    You Are the best mate!!!!

  • Pierre-Jules

    Fantastic! Easy! well done, Thanks

  • Hello! the bb step worked well. but then after normal itunes update from 4.1 i’m getting the sim blocked message. is that because in march 2013, it’s the version 6.1.2?

    • Sorry I’ve not tried with 6.1.2, but I doubt that is the reason.

  • A-Non

    step 9 says you downgraded to 5.13.04 but its 5.16.07 in the pic ha.

    • Hmm…not sure what happened there. I’m pretty sure I downgraded to 5.13.04. Since i took the picture after the iOS 6 upgrade, may be it changed then. Anyway, I don’t think it should matter.

  • Hello, please help me to solve my problem regarding “THE SIM CARD INSERTED INTHIS PHONE DOES NOT APPEARED TO BE SUPPORTED”.

    • Not sure why you would get this message. Just make sure you’ve inserted the right SIM card (GSM & CDMA SIMs cannot be interchanged.)

  • good job

  • cheetah khan

    hey buddy ..

    greetings from canada. Wanted to sell my moms old iphone 3gs. It had 6.15.00 baseband on it and because of your instructions i was able it to update it to ios 6.. before it wasnt able to activate… THANKS A LOT MAN!!

  • one question how do i find the IP address for Apple’s server i need to insert to fool it andi think i have it and thanx …someone sold me one that was upgraded and said nothing about it ty

  • i can use my home ips right …and can you give me an example like apple 3.555.677 / so i dont screw this up im a noob at this on any apple stuff thanx so much

  • oh i have the newer bootrom Model introduced: 2009

    Serial number: 849488G93NQ (cleaned up from ‘849488g93nq’)

    Production year: 2009

    Production week: 48 (December)

    Production number: 9801 (within this week)

    Model introduced: 2009

    Name: iPhone 3GS

    ModelCode: iphone_3gs

    Model Number: MC132

    Group1: iPhone

    Generation: 3

    Machine Model: iPhone2,1

    CPU speed: 600MHz

    Family name: A1303

    Screen size: 3.5 inch

    Screen resolution: 480×320 pixels

    Colour: White

    Capacity: 16GB

    Factory: 84 (Shenzhen, China)

  • Dear Naresh, like everyone else, congratulations on such a wonderful tutorial. I’ve been in this jailbreaking arenas for quite a while now and to get something to work in the first try it’s amazing. But i got trouble in step 10. A message appears saying “This device isn’t elegible for the requested build.” this while in DFU mode or in normal mode. Please please help me! thank you! it’s an iphone 3gs newboot rom with unlocked imei

    • I have fixed the issue. I just had to take the risk, and i upgraded to 6.1.3 instead of 6.0.1. It worked great. But an important step for someone that might read this, my phone before going to 4.1, in your steps, didn’t recongize the sim, but when downgraded to that, it got signal. so from then on i just figured that the unlock had taken effect and then i deciced to upgrade to 6.1.3 since 6.0.1 is not elegible, also for that upgrade to be complete i had to remove the line for etc/hosts/. Thanks Naresh, you saved the old 3GS =D

  • Taras

    Thanks a lot for great tutorial!

  • Rodrigo Dias

    Worked for me aswell!! Nice!! Thank you!

  • Pawan

    Hi Naresh
    I do not see the pineapple logo on my scree after the kernel step of redsnow
    Please help

  • Nemanja Gacevic

    i have 3gs bb 6.15.0 i ve updated it from 4.1 ios to ios 6.1.3 and now i can`t activate .. it said “server is unvailable try again later if this problem countinue contact iphone ..” sth like that . it was jailbroken before updateing! what to do ? To follow this tutorial or what ?

  • danielord

    OMG! I LOVE YOU!!! IT WORKSSSS 😀 (yes, I’m screaming)

  • Adam Daieh

    I’m going to try this iphone factory unlock. Hope it work for me too.

  • maha zamir

    why am i getting this “the connected device doesn’nt support unthetered options” please help ????

  • Hamza Arbiyani

    i do the exact steps and downgraded baseband but still its showing no service?

  • Dave West

    How can I backup iPhone when iTunes won’t recognize iPhone.

  • phaniraja

    hi guys i just upgraded my ios to 6.1.6 in iphone 3gs and jailbreaked it and works fine untill i wont swith off my mobile once my mobile gets restart it just showing no service and again i need to boot it using ultrasnow can i get an solution for not using ultrasnow again and again…..modem firmware 06.15.00

  • Apurva

    exact same situation but my phone’s power button doesn’t work so can’t put the phone in DFU mode. Its stuck at the steps for activation. on 6.1.6 and baseband 6.15.00 . Downloaded the Ipsw for 5.1.1 and created a custom IPSW for DFU mode but itunes wont even allow to restore with this ipsw because it doesn’t even recognize the phone till its activated or jailbroken.

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