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How To Downgrade iPhone 3.1 Baseband From 05.11.07 to 04.26.08

Download BasebandThough it’s warned by the iPhone Dev Team not to upgrade your iPhone OS directly via iTunes. I’ve got quite a number of emails from iPhone jailbreakers telling that:

Oh! I accidentally upgraded my iPhone 3G to firmware 3.1 by iTunes. After upgrade, I lost the jailbreak and the unlock. Now, I can’t make call with my iPhone. Even I jailbreak it again, it still doesn’t work and with no service. Any solution?

Probably you’re facing the same problem. As you may not know, the iPhone OS 3.1 also comes with a baseband update to 05.11.07 for iPhone 3G. However, the Ultrasn0w (i.e. the iPhone unlock tool) cannot unlock this version of baseband. It can only handle the lower baseband version 04.26.08. That is the reason why we emphasize not to upgrade to iPhone 3.1 via iTunes directly, particular you need to use ultrasn0w for unlocking.

Fortunately, there is a solution for that, though not for all iPhones. Thanks for the developers of Fuzzyband Downgrader. Fuzzyband is a tool that allows you to downgrade the baseband from 05.11.07 to 04.28.06. By downgrading the baseband, you can use ultrasn0w to unlock your iPhone again.

Cool, right? There is a catch, however. Fuzzyband can only support iPhone with bootloader 05.08 (5.8) from the factory. Only a limited number of iPhones that were released in the first few weeks of the iPhone 3G production cycle were loaded with the bootloader version. For other bootloader versions, I regret that you need to wait for iPhone Dev team to release the unlock solution. Not sure your bootloader version? Fuzzyband will take care that for you and verify if your iPhone is using the valid bootloader version.

Okay, here we go. Note that this guide is for iPhone 3G ONLY.

Downgrade Baseband from 05.11.07 to 04.26.08

1. First, you need to jailbreak your iPhone. If you’re using Mac, follow the step-by-step jailbreak guide for iPhone 3.1 to jailbreak your iPhone. For Windows users, you can restore back to iPhone 3.0 OS first, followed with jailbreak using redsn0w. You can follow this downgrade guide for details.

2. Once jailbroken, launch Cydia and search for “Fuzzyband”. Then install the application.

Search Fuzzyband in CydiaInstall Fuzzyband

3. After installation, go back to home screen and tap “Fuzzyband” to launch it.

4. Tap the “Downgrade” button to kick off the baseband downgrade.

Fuzzyband Downgrade for iPhone 3.1 Baseband

Once you complete the baseband downgrade to 04.26.08 successfully, you can download ultrasn0w to unlock your iPhone. For instructions, you can follow the step by step unlock guide using ultrasn0w.

Let me know if this solution works for you. I hope Fuzzyband can help some of you to recover your iPhone, for which was accidentally upgraded to iPhone OS 3.1.

About Simon Ng

Founder, developer and chief blogger of

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49 Responses to How To Downgrade iPhone 3.1 Baseband From 05.11.07 to 04.26.08

  1. mikey September 27, 2009 at 10:51 pm #

    accidently upgraded to 3.1 now wanted to downgrade it to 3.0 but getting an error 1015 towards the end (about 70%) of restoring the firmware 3.0 . I tried it with itune 8.2 and again with itune 9. same result so I restored back to 3.1 now waiting …….. for news

    • vu October 13, 2009 at 9:15 am #

      use quickpwn 221 restone

  2. iPhone Round Up September 28, 2009 at 11:28 am #

    Thanks for the iPhone information that you’ve shared in this post.

  3. UrbanZ September 28, 2009 at 6:11 pm #

    When you have the error 1015 close the itunes and open the QUICKPWN –> (download link), and follow the instruction that appears in message (Power button + Home button (15s), Release the home button and wait 2s power button) you will see the apple logo
    (this is for windows)

    But if you have the baseband 05.11.07 this don’t downgrade the baseband to 4.6!

    Sorry my english, i’m portuguese

  4. Azli My October 4, 2009 at 12:20 pm #

    hi, the fuzzyband solution is only for iphone with bootloader 5.8. i had one but my bootloader is 5.9. could u help me how can i unlock my iphone please…

    • UrbanZ October 4, 2009 at 5:31 pm #

      I have the same problem, i can downgrade my baseband 05.11.07 because my bootloader is 5.9. =/

      • Simon Ng October 4, 2009 at 8:08 pm #

        @Urbanz, there is no way to downgrade baseband for bootloader 5.9 for now. Please be patient and wait for iPhone Dev team to release an unlock solution.

      • mikey October 6, 2009 at 1:58 pm #

        Thanxs buddy for helping me out with ‘the 1015 error’ solution now I m wainting for the unlock just like u guys…….. let me know when the unlock solution comes up. Cheers

  5. Liang Zhou October 14, 2009 at 7:57 am #

    OMG!!! I am having the same problem, but because my bootloader is 5.9…on 3G firmwire 3.0… this is scary because I do not understand why Apple have to release such phone out when they do not have the full responsibility on the phone…this is really crazy. How can you buy the phone and still not be able to use it due to crazy updates you do….I’m really pissed OFF…


    • Carla November 3, 2009 at 2:09 pm #

      yeah, that really sucks!

  6. marcus October 16, 2009 at 12:15 am #

    I was woundering if I can downgrade my firmware? Because my bootloader version is 06.04 and is there some way to to it right now? And fuzzyband says “NOT SUPPORTED” for that. it says only working for bootloader 05.08

    ???? HELP ????

  7. UrbanZ October 16, 2009 at 12:38 am #

    Yes you can downgrade your firmware, but you can’t downgrade baseband, you need bootloader v. 5.8 to do this process =S

    I still waiting for solution =/

  8. marcus October 16, 2009 at 12:50 am #

    Okey I See..

    So if I want to unlock my phone I need to wait til bootloader v 5.8 comes out?

    Do you know how long this going to take before it release?

  9. UrbanZ October 16, 2009 at 1:52 am #

    this process only work with old bootloader (5.8), don’t have a solution to bootloader higher than 5.8. Only wait for new release of fuzzyband or dev team with new ultrasn0w. =S

  10. Crowsoul October 16, 2009 at 7:54 pm #

    Would that unlock my 3GS that came out of the box with 3.1.2 and a 05.11.07 baseband?

    • Simon Ng October 17, 2009 at 12:20 am #

      @Crowsoul, it’s very likely the latest batch of iPhone 3GS comes with baseband 05.11.07.

  11. amin October 19, 2009 at 6:27 pm #

    I install that but when open it show not supported.
    ” this software cannot be used on iphone os 3.0 ; you must downgrade to 2.2.1 or lower.”
    If I downgrade can I change my basebond? from 5.11.7 to lower!
    because I dont have antena!!!

    • Sam January 21, 2010 at 2:26 am #

      Baseband 5.11.7 can be downgraded using Fuzzyband tool only if bootloader version is 5.8 or below of your Iphone, if it is 5.9, fuzzyband can not downgrade baseband of your iPhone. You have to find another way, I am also looking for one. Please let me know too if you find one. Thanks!

  12. UrbanZ October 19, 2009 at 6:46 pm #

    Download fuzzyband, not the “3g fuzzyband downgrade”

    Good luck

  13. amin October 19, 2009 at 7:11 pm #

    So thanks sir
    I do that but my bootloader is 5.9
    Can I change my boot loader?

  14. UrbanZ# October 19, 2009 at 8:09 pm #

    Sorry, but you can change bootloader the difference between 5.8 and 5.9 is not only software, have hardware to.
    I’m in the same situation, wait for dev team solution :(

  15. UrbanZ# October 20, 2009 at 1:16 am #

    Good news guys and girls, geohot is working in a solution to unlock baseband 05.11

    All info here

  16. Amin October 20, 2009 at 3:42 pm #

    this site don’t open. It has some problem!

  17. Paramveer Bhatia October 20, 2009 at 4:59 pm #

    I have iphone 3gs on that i have 3.1.2 firmware with a baseband 05.11.07 now i am able to unlock my iphone so i need help plz tell me if any baseband downgrade option or unlock option for iphone 3gs…….thnx in advance

  18. Paramveer Bhatia October 20, 2009 at 5:00 pm #

    I have iphone 3gs on that i have 3.1.2 firmware with a baseband 05.11.07 now i am not able to unlock my iphone so i need help plz tell me if any baseband downgrade option or unlock option for iphone 3gs…….thnx in advance

    • Simon Ng October 20, 2009 at 9:44 pm #

      @Paramveer, for the time being, there is no solution to unlock that version of baseband.

  19. UrbanZ October 21, 2009 at 1:55 am #

    Exactly for now no solution, but geohot and the rest of the team is working to find a new exploit to unlock this baseband.

  20. krasimir October 21, 2009 at 6:13 am #

    Hi Simon,
    I read everything, but still i’ll ask what i can do with iphone 3G 3.0 (i don’t know the history of this phone) after i restore it and giving me error 1015, then i actived and jailbreak it with redsn0w 8, i try fuzzyband downgrader but i get message “not supported” :Bootloader Version 05.09 and baseband version 05.11.07
    so do i have to wait for new software or there is some solution

  21. stephanie October 30, 2009 at 3:19 am #

    its telling me downgrading will only work with baseband bootloader 05.08??? please help being trying to unlock this thing for months!!! arghhhh!!!!

  22. UrbanZ# October 30, 2009 at 4:01 am #

    Wait, Geohot is working in unlock for bb 05.11.07

    see this –>

  23. iphoneR November 2, 2009 at 1:29 pm #


    Geohot is releasing an unlock for iPhone Baseband Version 05.11.07 on 3/11/2009.
    Does this mean if I have Bootloader Version 5.9 with 05.11.07 I will be able to downgrade my boot loader to version 4.6 if I wanted to change the IMEI?

  24. UrbanZ# November 2, 2009 at 7:22 pm #

    Wrong information, geohot release blacksn0w on 04-11-09.

    You be able to change imei in iPhone classic.

  25. iphoneR November 2, 2009 at 8:52 pm #

    Hi UrbanZ#,

    Change the IMEI in iPhone classic?
    Can you explain?

  26. UrbanZ# November 3, 2009 at 12:46 am #

    See this ->


  27. iphoneR November 3, 2009 at 7:08 am #


    That shows how to IMEI change with BL 4.6
    iPhone’s updated with 3.1.2 would have a later version than BL 4.6, right?

  28. iphoneR November 3, 2009 at 7:46 am #

    Upgrading the iPhone firmware to version 3.1.2, updates the Bootloader to version 5.9

    Is it possible to downgrade the Bootloader from version 5.9 to version 4.6 and using ziphone to change the IMEI?

    • Simon Ng November 4, 2009 at 12:58 am #

      @iPhoneR, no need to downgrade the baseband. GeoHot will release the unlock solution to unlock iPhone 3.1.2. The application is called blacksn0w. I’ll soon post an update about that.

  29. Carla November 3, 2009 at 2:05 pm #

    oops! sorry i followed the comments & found out that fuzzyband downgrader is only capable of downgrading 5.8 baseband to 4.26.08, thanks again. Im sad about this news.

  30. iphoneR November 4, 2009 at 7:09 am #

    @Simon NG – I have to downgrade the BOOTLOADER from version 5.9/6.2 (whatever firmware 3.1.2 upgrades it too) to BOOTLOADER version 4.6 (as shown: so I’m able to change the IMEI.

  31. Imzee November 6, 2009 at 9:44 am #

    hi mine says my bootloader version is 06.04 and wont let me downgrade is there any way to fix this please

    thank you

  32. marcus November 6, 2009 at 11:02 am #

    Okey. I have the same problem like you Imzee before… IF you want to UNLOCK it. Just download blacksn0w and install it on your iphone, then your are good to go!

    Good look


    There your go if you WANT TO UNLOCK Iphone that have 3.1.2 Firmware (doesent really matter what bootloader your have) peace

    • Aaron November 18, 2009 at 4:15 pm #

      All, i have a iphone 3g and downgrade from 3.1 to 3.0. My bootloader is 6.4. Has anybody successfully unlock the phone yet?

      • Simon Ng November 18, 2009 at 10:59 pm #


        GeoHot has released a new jailbreak and unlock tool to handle the latest version of baseband. You do not need to tackle with the downgrade anymore. Just check out this jailbreak guide and unlock your iPhone with blacksn0w.

  33. Tomer December 20, 2009 at 4:59 am #

    Note that this is also a great tool for upgrading your baseband to a desired firmware (assuming you used a custom firmware thus preserving an old FW (2.28.00, for example) that doesn’t work with ultrasn0w)

    helped me a lot

  34. Sadboy December 20, 2009 at 2:20 pm #

    Hello Simon. I am the lucky guy who didn’t update his phone via iTunes this time. I am having 3.0 in my iPhone. Can you please help me how to get bitesms application in my iPhone. Previously it was free but now they are charging. Problem is that don’t have credit card here in Pakistan, so please help me how to get bitesms. I’ll be very thankfull to you. Regards

    • Simon Ng December 20, 2009 at 11:38 pm #

      @Sadboy, do you have a Paypal account? You can make the payment via Paypal. Otherwise, you need to have a credit card for the payment.

  35. donkie May 3, 2010 at 11:53 pm #

    my bootloader 6.4 Lolz

  36. HB May 20, 2010 at 5:00 am #

    I have a new iphone 3g Which i had unlocked using redsn0w

    Firmware 3.1.3
    baseband 05.12.01
    bootloader 06.04 .

    Can anyone tell how to unlock this phone?

  37. luc1f3r July 21, 2010 at 10:48 pm #

    hey guys ive got a 3.1.3 bl 6.4 needing to change the imie as its been reported lost by the previous owner and yes it was lost :D i know cause i found it…. anywys im askin anyone that doesnt mind helpin someone thats not exactly honest… i refuse to give it back for one reason alone.. its worth a heap and well.. I FKN FOUND IT :/! aaanyways.. if anyone knnows hot to either downgrade the BL or change the imie without to much hassle or hardware variations pls email me at [email protected]

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