application not compatibleIf like me you are still running on OS 3.0, you sometimes probably encounter an issue when trying to download an application from the App Store. The issue in question is that “this application requires the iPhone 3.1 firmware update”, which comes under the form of a popup saying “Application Not Compatible”.

There is a quick and dirty fix for that: simply install the FWchanger app from Cydia.

Firmware Changer is an app that lets you change the plist file that contains the version of firmware you are running. This is useful for things that refuse to install or run on one firmware version even though they can. Note this only changes the reported firmware, not the actual firmware.

After installing FWchanger, launch the app and enter a fake firmware and build.

Hit “Set Custom Firmware”, and voila! Go to Settings > General > About and you should see your fake firmware there.

Now you can trick these applications that require you to be on 3.1 into thinking you are running OS 3.1 even though you are not. This works for older 2.X firmwares as well. Note that it doesn’t always work as advertised but in most cases, it was spot on for me.

Pretty slick, huh?

  • AG

    Yea this is pretty slick I’m going to download this app right now!!!
    -Jailbreak 4 Life-

  • Marc

    My iPhone crashed after installing this app. It won’t start. I see the apple symbol and nothing happens anymore. Please help me!!!!

  • AG

    Mines did too I uninstalled it

  • AG


    Hold the hold and home button until the power cut off and let go of it wen it comes back on let me know what happens

  • Marc


    nothing happens. Still the same. Starting it and only the apple is visible.

  • Damn! I’m sorry to see you guys are having issue with that. It worked like a charm for me.

  • Fred

    Too bad it does not work with Dropbox, i think mainly because dropbox have features from the 3.1 SDK.

  • Marauder

    Gotta reboot after installing but before trying to use. I had no problems.

  • AG

    Well u might hve to re-jailbreak ur iPhone or iPod that’s the only solution that I know will work if all u see is the apple my iPod did that before and I re-jailbroke it and it worked sorry but that’s the only thing I can come up with that I know will work

  • Marc


    can’t jailbreak because I get no connection to the computer.

  • AG

    all u have to do is put it in DFU mdoe to jailbreak it ur computer detects it iTunes just doesn’t detect it

  • Marc


    Can’t put my iPhone neiter in DFU Mode nor in Restore Mode. I just can see the Apple Icon.

  • eggbert

    I also had the apple logo with the progress bar. It looked like it was going to hang but finally went back to normal.

    I installed red laser, which is one of the apps that won’t install < 3.1. The program would not work, it just opens and then closes. Same for the latest version of yelp.

  • Alan

    Hey sebastien, can you sync an iphone 3g/3gs with firmware 3.0.1 to itunes 9?

  • AG

    that’s impossible are u sure ur doing it right do u know how to put it in DFU mode?

  • JAS Nature

    I used it on my jailbroken 2G which i use for another phone number… not wanting to re jailbreak my phone i used this app and convinced my phone it was running 3.1 was able to download apps now that require 3.1 and i believe my 2G last update was 2.2 firmware… definitly works!!

  • Matt

    I tried to download Canabalt, and I was able to get farther than I would without the app, but after it started downloading a message came up saying I didn’t have 3.1, and then it killed the download.

  • Mike

    I downloaded and tried to download redlaser and it still said I had to upgrade…..

  • Marc


    I’m pretty sure but tell me how to do it.

  • Looks great.

  • AG
  • mac

    doesnt work for myspace

  • Has anyone gotten this to work with a 3GS? Or successfully recovered after trying it? I installed it before I realized that it was screwing things up for some people. I edited my /System/Library/CoreServices/SystemVersion.plist to hopefully get it back to what it’s supposed to be, but I am afraid to reboot my iPhone now. Really don’t want to loose my jailbreak and unlock by having to restore. Does anyone have a copy of their SystemVersion.plist to compare? This is what mine shows now, but I’m not sure that I got the productbuildversion right:

    1983-2009 Apple Inc.
    iPhone OS

  • D

    I downloaded it, but it doesn’t show up anywhere on my springboard, even though it does show as installed under “packages” in Cydia. Can anyone help

  • D

    Ok, I rebooted it and everything, still nothing. It DOES show up in “Categories” and Cydia, but not springboard. I used the search option, found it and it ran.

  • after faking my iphone to 3.1.3 all applications get installed which required new version 3.1 but when i try to open it closes immediately……………plz help if there any solution


  • semil

    i downgrade my iphone from 4.0 to 3.0 but i am not able to restore my backup….
    plz give me solution…
    thank you..

  • Eddie

    Just doesn’t work. Running on iphone4 with 4.0.1 (jb with limera1n) and you run this prog, pick a change, hit ‘save’ and **nothing** doesn’t do a darn thing.

    waste. fix your prog before distributing. I’d rather not be an alpha tester for you.

    Not ready for prime time.

  • Jdixn

    It’s not in cydia

  • Joeyyyyyyyyyyy

    Yeah.. Uhh… It’s not on cydia for me either..

  • Max

    its not in cydia help!

  • Young Radz

    i think they took it off cydia

  • Joeyyyyyyyyyyy

    Someone put it back!!!!!

  • Sturlei

    guys guys, you dont even need this you can change it by yourself.
    you just need one thing,
    1: IFile
    2: shh instald on iphone and iphone folder or WinSCP
    firs open IFile and then just go all the way back to the beginning of your shh folder.
    navigate: /System/Library/CoreServices
    and open SystemVersion.plist on Ifile just tep on it end tap Text Viewer on the computer open it with notepad end edit the line under ProductVersion there should you see your currently version of FW
    change it:
    (ex)4.3.2 and just save it. reboot and that’s it
    or just try this
    add source and there is the app calls Firmware 4.2.1 fake this is also good.

    • Adrian Dwyer

      it doesnt work for iphone 3g 4.2.1 it goes in and straight back out of the app so ill try ifile

  • asif

    Aweome.. Sturlei.. Ur the best man.. The ifile thing worked for me.. Thnx a ton..

  • haim

    did i can do it from ifunbox ?
    to ifunbox have total control on idevice.
    so maybe we can do it from ifunbox.
    please answer me as soon as possible.