How to jailbreak and unlock iPhone 3GS firmware by downgrading it from 3.1.3 to 3.1.2

iPhone

A lot of users upgraded their iPhone 3GS firmware from 3.1.2 to 3.1.3 without knowing the consequences. So, if you want to jailbreak and unlock it using blackra1n, you’ll have to downgrade to 3.1.2 but the modem firmware will still be 05.12.01. Remember, before trying this out, back up your data. If you end up bricking your iPhone, I won’t be responsible for it. ( Credit for this guide goes to Cliff who sent it in! )

  1. Uninstall iTunes 9.0.3 to from your computer. Remember to back up your data, and rename the iTunes library folder to something else.
  2. Download and install iTunes 8.2.1. Download 3.1.2 firmware to your computer. ( links at the end of this post ).
  3. Connect your phone to the computer and hold shift and click restore in iTunes. Select the 3.1.2 firmware file.
  4. The restore might get stuck and you’ll get an error 1015 message.
  5. Ignore it and reboot your iPhone using the power + home buttons.
  6. You’ll now see the USB and iTunes logo on the iPhone display. This means that firmware 3.1.2 is installed. But right now, the phone is stuck in a DFU loop.
  7. To fix this, you’ll need to use iRecovery.
  8. Once you’re out of the DFU loop, iTunes will ask you to sync with the old backup. We suggest you avoid that and opt to set up a new phone. iTunes will reactivate your iPhone.
  9. Follow our guide on how to jailbreak iPhone 3GS with OS 3.1.2 with blackra1n RC3.
  10. You can now unlock your iPhone using blackra1n RC3. Follow this guide for instructions.

If you are running into issues, follow this guide to jailbreak and unlock your iPhone 3GS.

If you are using iPhone 2G, 3G, iPod Touch 1G or 2G ( non-MC models) follow this guide to jailbreak OS 3.1.3 with redsn0w.

Download iTunes 8.2.1 (32 bit)

Download iTunes 8.2.1 (64 bit)

Download iPhone 3GS OS 3.1.2

Update: Use this guide to jailbreak iPhone 3G/3GS with OS 3.1.3/3.1.2 untethered! ( no unlock yet, though)

Note: This method doesn’t work anymore. follow this guide to jailbreak and unlock your iPhone 3GS.

About the Author

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92 comments

  1. Hi,

    Is the 3.1.3 firmware been jailbreak yet for the Iphone 3GS? Or are we still stuck in 3.1.3

  2. When ‘they’ do crack 3.1.3, where’s the best place to look for it?

  3. If anyone knows what they are talking about get this, I have a iPhone 3GS I was at 3.1.2 fully jailbroken, also had the previous version of itunes before this fuc%ed up 9.1 sh!t came out. Anyways my comp crashed, had to do full restore. so I downloaded itunes (the 9.1) and pluged my phone in and I still dont know why but managed to restore my phone with the 3.1.3 (my modem firmware is 05.12.01)
    can this be fixed???????????

  4. how can i use T-MOBIL in iphone 3gs mc model 3.1.3?
    i been using t-mobil before on 3.1.2 but i had to upgrade my phone to apple setting for some reason, now i cannt use t-mobil sim.
    is there any way to use t-mobil’s sim again?

  5. Any new information about when will we be able to unlock this 3.1.3 Iphone 3gs with Firmware of 5.12 please ?
    Any info will be helpfull , thanks

  6. I tried many times and I just get a message that says that my device isn’t compatible with the requested version.

    Any idea on how to get error 1015?

    1. same here,i got a 3gs 16 gig with 3.1.3,,it wont let me downgrade,,,how to do it ,any help?

  7. Hey,
    it is really easy to downgrade an iPhone from 3.1.3 to 3.1.2…

    There are a few things you have to Download before you start:
    -iRecovery
    -libusb-win32-filter-bin-0.1.12.1
    -iPhone Firmware 3.1.2
    -Blackra1n (if you wanna jailbreak your iPhone)

    The first thing you have to do is to change a file in windows.
    It is the file hosts. You can find that file here:
    c:/windows/system32/drivers/etc/
    you have to open that file as admin.
    In that file you have to go under the last line n add this:
    74.208.10.249 gs.apple.com

    If you have changed that restart your Computer.

    After the restart you can open iTunes n then you put your iPhone into DFU-mode. (hold power+home for 10 seconds n then hold only home for 10 seconds)

    Then you have to hold the shift button and press restore in iTunes…the you have to choose your downloaded firmware 3.1.2

    iTunes will restore your iPhone then…after you have done that you will get a message that it didn't work. (1015 code)
    But this is Normal!

    Now you have to install libusb…when it's done open lib usb and then run cmd from windows.

    put irecovery on the desktop n then do that:
    You will see there c:/Users/yourname>

    You have to add this:
    cd desktop
    irecovery -s
    setenv auto-boot true
    saveenv
    exit
    reboot

    After that your iPhone will come out of recovery mode n it is done!

    You can now (if you iPhone is activated then) jailbreak your iPhone with blackra1n

  8. Hi – Just got a new iphone 3gs version 3.1.3 model mc133b – how can I jailbreak it? )-8

  10. Thank you very very much david. I have spent ages trying to downgrade the firmware to 3.1.2 and your method was the only one that worked :)

  11. 1- when i try to give the version 3.1.2 it tells me that its a not compatibe.
    2- the iRecovery worked well to recover it basck from safe or DFU mode

  12. hi david,

    please help, after adding irecovery -s in cmd, it says Got USB No iphone/ipod found, i'm trying to downgrade an iphone 3GS 4.0.1,

    Thank you

    1. You need to be in recovery mode, then do the iRecovery step and it will run. You can enter recovery mode manually or by using RecBoot for example. However, at step 8, iTunes is not asking anything else but to restore the iPhone again, so it’s this loop that I need to get out of now.

  13. PLEASE HELP!!
    Tried to break my 3Gs using snOwbreeze and something went wrong, whiped everything! Wont even restore any itunes software ahhhhhh!
    PLEASE HELP!!

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