Apr 12

I was planning to review BootNeuter together with the release of WinPwn.
But as it still hasn’t been released due to several little bugs that the developer want’s to fix, i will go ahead and review the BootNeuter app first.

I’ve had a lot of people who ask me, what is BootNeuter and why do i need it.

First let me explain what it does.

BootNeuter let’s you switch between bootloaders (for info about bootloader and baseband go here).

So why do i want to switch bootloader? Without going into to much technical details (if you’d like, we can talk about this, just drop me a mail), for improved Google Location and improved battery life if you’re running 1.1.3 or 1.1.4.

People who are running older firmware versions, should not upgrade to the BL 4.6

Ok now that we have that out of the way, let’s discuss this neutering thing.

What is neutering your bootloader?


-A neutered bootloader gives you absolute control over your baseband. The normal restrictions invoked by apple are completely removed !
-The baseband is no longer integrity-checked
-Can be patched (unlocked or other custom modifications)
-4.6BL will even run with patched baseband ??� no need to revert to 3.9BL even with most recent firmware
Secpack restrictions are removed
-You are free to downgrade your baseband using bbupdater without having to run ieraser/ienew first.
-No longer does the ???greater than??? (4.6BL) or ???greater than or equal??? (3.9BL) rule apply. You can arbitrarily go up and down regardless of what secpacks you use.
Secpack signatures are ignored
-The RSA encrypted header is no longer checked for correct hash values by the bootloader
-The *.fls files can be patched and fed to bbupdater directly
-A copy of the last used secpack will be saved at a03c0000, retrievable via norz or similar dumpers. Not that secpacks even matter anymore.
-Your neuter selection survives iTunes restores and updates

Let’s have a look at the app Bootneuter itself
Warning ! You must be on fw 1.1.4 to be able to bootneuter your bootloader with BootNeuter !!

1) You can locate the app in the tools category of the installer, if you haven’t pwned your device..

2) Before you launch BootNeuter, switch off your Wireless. and make sure your battery is high enough.

3) Let’s launch the app.

4) While the app starts it will determine your settings.

5) when the app stars you can chose your Bootloader version. If you are on 1.1.3 or 1.1.4 and see that your baseband is 3.9.
I recommend that you select the 4.6, activate the neuter and the unlock swithc.

After that press flash and wait some time. The procedure can take some time, so don’t swith of your iPhone while it’s busy !!!

I’ll include some screenshots of me going back to 3.9.
Tjhe principle is the same for upgrading as for downgrading.

The process goes in several stages.

a) First the Bootloader will be flashed.
b) 2nd the Baseband will be flashed.

Et voila .. you’re iPhone’s bootloader and baseband have been bootneutered.

Now all you have to do , is reboot your iPhone , and it’s done.

This big app is available in the Installer.app through the Sendowski packaging source, see our sources page.


Ps: People with problems, just mail me or leave a msg.

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121 Responses to “Upgrade or downgrade your bootloader with BootNeuter”

  1. gavriella Says:

    after i finish flashing it and put my sim card in, it says tmobile in the corner but i still continues to say “different sim” and “connect to itunes” help please!!?

  2. nicole Says:

    so I’m completely and utterly incompetent when it comes to this stuff,
    but i JUST bought this iphone and its not compatible with rogers,
    which of course is who my current contract is with.
    I DLed blackra1n, and got cydia, then got this bootneuter 2.1,
    Hoping to unlock my phone evetually getting to this anysim compatability thing,
    but when ever i open bootneuter it just like freezes…
    I cant select neuter fake black or unlock.
    it just stops :(

  3. Brandon Says:

    hey im sure therse is lots of people that upgraded well i just happen to get ahold of a 2G its got firmware 3.1.2 well i am not sure whats its called jailbreak/unlock i used blackrain to be able to use the phone but now i need to make it where i can use ANY sim card .. not sure how to do this please someone help please email me jokerhdc@yahoo.com thanks hope someone can help

  4. ScottD Says:

    Ok, here is my problem. I just put my cingular sim in a Iphone 3G with latest version of the Iphone Software 3.1.2 and Jailbroke and hacked with Blackrain and the only problem I have is no data connection. When I use Redsnow it asked for my bin files and I had no problem with 3.0
    What do I have to do to make this work?

  5. Gus Says:

    Were you able to find a solution to what you said?

    mine still says the “different sim” and “connect to itunes” with the tmobile in the corner =/

  6. Gus Says:

    email me if you have a solution, please?


  7. Calvin Starnes Says:

    Is it safe to delete the bootneuter app off your iPhone once you’ve flashed and unlocked your phone? I had a fully updated 2G to 3.1.2 that I bootneutered and now I want to get rid of the app if I no longer need it.

  8. Sara Says:

    I unlock 3G iPhones alot, but latly have been doing 2G. Why am I getting an ERROR 2? I have successfully done 2 iPhones, on my third one I keep getting this. And some CommCenter message…Any help? Thanks

  9. Rizan Says:

    hi multinova,
    my prblm is tht when i upgraded my iphone to 2.0 and i didnt know anything abt this bootneuter thingy..but i by mistake went into it and pressed another version of BL then it said phone is flashing and then restarted and it was stuck on the apple logo forever i tried all the ways of restoring the firmware but never worked out..it says error when restoring.and my phone is 2G 8GB.. and it remains a brick for 3yrs.i used only a week.so worried..Search all over the net nothing worked out.Wish u can help me out plz plz….It wud b so so helpful if u could plz help me..im expecting ur reply.plz help me out fix this thing.plzzz

  10. lisa Says:

    i got a iphone that was unlocked but when i put it into my itunes it asked me to upgrade to the new software 3.1.2 or somethng like that, so i did.
    noy my iphone is telling me to insert a at&t sim card and i obviously dont have one. what can i do to fix this ?
    please help mee..

  11. Sib Says:

    yo, can u tell me if I can downgrade my baseband somehow??
    I got an iPhone 3G and my baseband is 04.05.04_G and i don’t get no service anymore since i once upgraded it to the latest version, which was a big mistake!!

  12. Peter A Says:

    PLEASE HELP. I am currently runnin a 3.1.2 Blackra1n jailbroken 2g iphone.

    but i want to unlock my phone, buit it doesnt work. it says different simcard inserted….PLEASE HELP …….i ran 3.9 BL and even 4.6 BL but it still doesnt work!


    EMAIL: knowledgeable@hotmail.co.uk


  13. tv Says:

    just got a first gen (silver black 16GB). it has 3.1.2. Jailbroken with Blackra1n) It has an old ATT sim and I thought I could swap my sim in…when I do i get the itunes icon and cable. When I put the old sim in…works fine (no phone though). Any ideas?

  14. huy Says:

    i got same issue with (tv ) i try to put my sim on and i just pop up itines icon and connector that all.i cant even turn off or go in side with any program..ahve any idea please email me let me know..thank you ( leechengx@yahoo.com)

  15. Mario ponce Says:


  16. Dorothy Says:

    Sorry – there was a typo on my last post.

    I tried to update my iPhone to the new OS 3.1 and iTunes will not let me update without signing a 2 year data contract. My phone was unlocked (although I had AT&T for voice calling and no data). Is it too late to unlock my phone again?

    How can I install the OS 3.1 and unlock my phone WITHOUT using iTunes?? Please help!

  17. javi Says:

    can u emial me on how to unlock a iphone to use on my tmobile account.. thanks

  18. Peter Says:

    Hi… followed all the instructions and not working. I have the original iphone 2g, with 3.1.2 and modem firmware 04.05.04_G

    I ran blackrain to put cydia on the phone, then i searched and loaded bootneuter.
    I run bootneuter turning neuter ON and unlock ON, and version 3.9.

    I get error : the bootloader flash failed error 5

  19. deshun Says:

    i have the same issue as tv and huy. phone is jailbroken with blackra1n, bootneuter is set into place and says it is unlocked, place in t-mobile sim and though it says t-mobile in oppose to at&t in the top left corner. the “connect to itunes” screen won’t go away. any suggestions would help.

  20. K'em Says:

    i upgrade my iphone to 3.1.3 unknow to me that it can not be unlock plese help me with solution.

  21. telo Says:

    i updated an iphone 2g to 3,1,3 too, I know how to unlock it I just need a binary code baseband bootloader 3.9 and 4.6. Do anyone knows where can I find these two?

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