Problems upgrading 3Gs 4.0 to 4.0.1 in order to jailbreak/unlock.

Discussion in 'Jailbreaks and iOS Hacks' started by zillawag, Oct 5, 2010.

  1. zillawag macrumors newbie

    May 21, 2008
    I have an already activated 3Gs iPhone running 4.0 with firmware 5.13.04 and the old boot 359.3, and I'm trying to jailbreak/unlock using Mac OS X.

    After much research I've found that I'm supposed to upgrade to 4.0.1 in order to use, then ultrasn0w for the unlock.

    I can't directly upgrade via iTunes, since Apple is no longer supporting 4.0.1 (instead it only wants me to upgrade to 4.1, which apparently cannot be jailbroken/unlocked on the 3Gs, as far as I know). I found the proper 4.0.1 ipsw file and downloaded it, but when trying to do the option/restore in iTunes, it won't let me. Apparently, iTunes tries to verify the file and refuses it since 4.0.1 is no longer supported.

    This site,, shows a way to bypass Apple's verification process by tricking iTunes into contacting Cydia instead. But I have a few questions that I'm hoping you can help me with.

    1) Is there a better/easier way to upgrade to 4.0.1?
    2) Saurik (on the site I linked) mentions that we need to find the host file, yet only gives the full path for Windows, and I can't seem to find the file on my Mac. Can anyone show me the full path?
    3) Once I find it, I might need some help with "add the following entry to the bottom of the file:" if anyone has done this before?
    4) Will this automatically save my SHSH blobs or do I need to manually do it?
    5) If the phone was synced to the original owner's computer, and I use my computer to unlock it, will I still be able to connect to a 3rd or 4th computer to sync it once unlocked?

    Any and all answers are much appreciated! Thanks!
  2. Myzhi macrumors 6502a


    Dec 15, 2009
    You can JB 4.0. Using Safari on the phone, go to and follow the instructions. After, make sure to install the PDF patch to close security exploit.

    And, only difference between 4.0 or 4.0.1 is how signal bars are display. No need to upgrade to 4.0.1.
  3. zillawag thread starter macrumors newbie

    May 21, 2008
    Thanks for responding. For this phone, I will do that.

    I'm still curious as to how someone can upgrade to a non-Apple-supported iOS, which at the moment is anything less than 4.1. I did see several people ask the same questions on different forums with no answers. So for someone who has an older phone (2G, 3G, 3Gs), and would like to upgrade to 4.0 for the JB/unlock, can anyone tell us how to do it?

    Also, once jailbroken/unlocked, is there still a maximum number of computers that an iPhone can connect with?

    Thanks again.
  4. Myzhi macrumors 6502a


    Dec 15, 2009
    For 2G and 3G, it's pretty easy to update to firmware you want.

    With 3GS and IP4, Apple added SHSH security check so you can't install firmware they don't allow. You can trick iTunes into allowing you to install old firmware by saving those files when Apple was still sending them out. If you want more info, use search feature.
  5. maturola macrumors 68040


    Oct 29, 2007
    Atlanta, GA
    Take a look at this thread i posted a few days ago with a bunch of information about jailbreaking, maybe it will give you a better understanding on how things works. -

    As far as upgrading to a non-current firmware (or what you called "non-Apple-supported iOS") all you need are your SHSH if you on a 3GS (or any other iDevice release after the 3GS, > iPad, iTouch 3G/4G, Apple TV, etc). You can manually point your computer to think that Cydia server are Apple to get itunes Tricked into loading that "old" firmware (as you saw on that lick for the guide) or you can use a Program called Tiny Umbrella that does that for you Automatically, just run it, start the TSS server and Option+restore your iDevice.

    Older devices iPhone 2G, itouch 1G/2G don;t have the SHSH check up, so they can update using other ways.

    That is pretty much not only the easier way to do it, but pretty much the only way to do it.

    The jailbreaking will depend on what firmware you are (or what is the highest firmware you can currently load) each firmware have a different upgrade/update path. 4.0 and 4.0.1 were "userland" exploits so they only required to visit a website, other Jailbreaker have been more involve (and the next jailbreake 4.1/4.2 I am pretty sure it will require more steps, we'll know for sure soon)

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