Need advice to JB a 3GS iOS 5

Discussion in 'Jailbreaks and iOS Hacks' started by Fredini, Nov 3, 2011.

  1. Fredini macrumors newbie

    Nov 3, 2011
    Hi all,
    I have an iPhone 3GS that's been upgraded to iOS 5. I want to jailbreak it to work on tmobile. Its for my teenage daughter, so I want to have a non tethered solution.

    Questions I have:
    1) Should I downgrade it to 4.x before jailbreaking it? if yes, what version?

    2) Is Redsn0w the way to go? Again, this needs to be a non tethered solution.

    any guidance would be appreciated as I am a JB n00b! :eek:

  2. Crystal-RX macrumors 68030


    Dec 22, 2008
    Seattle, WA USA
    Here is what you need to do;

    1. Download Idetector and run it to see of your phone has old bootrom or new bootrom.
    a. If your phone has old bootrom, then you are good to go with OS5 because you will have untethered jailbreak.
    b. If you phone has new bootrom, then you need to downgrade it to 4.1 because Apple still sign this firmware and you will be okay to downgrade it.

    2. Please use redsn0w to jailbreak your phone.

    3. If you want to unlock your phone so you can use it on T-Mobile, then only option you have at the moment is to install an Ipad baseband on your phone. There are consequences with your phone having ipad baseband. You can search for these consequences. Again, if you decide to proceed with this, please use redsn0w to install this ipad baseband, then unlock it with ultrasn0w. or/and have all the tutorials for you to do these.

    Good luck!
  3. Fredini thread starter macrumors newbie

    Nov 3, 2011
    Can someone explain this baseband issue for me? What is the baseband- a piece of hardware? Is there a good resource online that explains this?
  4. maturola macrumors 68040


    Oct 29, 2007
    Atlanta, GA
    Try this..
    Jailbreak FAQ and commonly use Terminology + Guides

    BaseBand: Based band is the name given to the modem (radio) firmware, this is the code that control the hardware that allow the phone to communicate with the network, it hold the network stack (think about it like the language that the Network towers speaks).

    These 2 may also help understand why the baseband is important.

    Bootrom: Permanent code written on the Read Only Memory (ROM) of the Microcontroller, This allow the device to Boot and Initialized all the Peripherials, IOs and some hardware components. Since it is written on read only memory, this code cannot be update or change.

    Unlocking: In some cases the baseband is force to communicate only with an specific network (Lock to that network). Unlocking refers to the process of modifying, tricking or working around this restriction and let the baseband to communicate with any compatible network.
  5. sfjava macrumors member

    Mar 22, 2011
    Another option is to pay someone at craiglist to do it for $15 to $20. It is probably a rip off, but for it may be a worthwhile for some.
  6. sbddude macrumors 6502a

    Sep 27, 2010
    Nor Cal, USA

    Honestly I think you are better off selling the 3GS as is and buying one that is already unlocked - get one that does NOT have 06.15 baseband (look at settings > general > about > modem firmware).

    If it has 06.15, GPS will probably NOT work.
  7. Fredini, Nov 3, 2011
    Last edited: Nov 3, 2011

    Fredini thread starter macrumors newbie

    Nov 3, 2011
    Hi Everyone,
    Thanks for all the responses! I'm now sitting with everything in front of me and ready to try this. Again- I am trying to jailbreak the device, then unlock it to work on tmobile. I want an untethered solution.

    about the device
    - OS is currently iOS 5
    - The Bootrom is iBoot-359.3, which is good because it is the old one!
    - Modem Firmware is 05.16.05
    - I am using OSX, not windows

    So, my questions are:
    1) Should I revert the phone to iOS4.something or jailbreak it under ios 5? If I revert do i revert to 4.1, 4.35, or something in between?

    2) Sounds like I have no choice but to do the baseband update to ipad baseband (6.15)- is this correct?

    3) Will I do all this with the old AT&T simcard in it or no sim card in it? or doesn't it matter?
    I wait to put the tmobile simcard in until after I unlock, right?

    From all that I am reading, it sounds like I want to run Redsn0w on top of iOS 5 and install the ipad Baseband. Then I will run Ultrasn0w to unlock it. It sounds like this may break GPS on the device, but we can live with that.

    Does this sound like the right approach?
    Thanks for the advice!
  8. Crystal-RX macrumors 68030


    Dec 22, 2008
    Seattle, WA USA
    1. Since you have old bootrom, you will have untethered jailbreak with OS5, so you don't need to downgrade its firmware.
    2. You are correct, the only option is to install Ipad baseband if you want to unlock it.
    3. It doesn't matter. Once you unlock it, they it will work with any GSM sim card.

    use the redsn0w to jailbreak it and install ipad baseband, then unlock with ultrasn0w.

    Again, you can get tutorial on how to do this from or/and
  9. Fredini thread starter macrumors newbie

    Nov 3, 2011
    Yay! It worked!
    Thanks so much- sorry for all the questions but I didn't want to brick it!
  10. Crystal-RX macrumors 68030


    Dec 22, 2008
    Seattle, WA USA
  11. vong macrumors 6502a


    Jan 31, 2010
    I thought you could not downgrade your phone unless you got SHSH saved?
  12. Crystal-RX macrumors 68030


    Dec 22, 2008
    Seattle, WA USA
    For some reason, Apple still signs 4.1 firmware for 3GS. So, you do not need SHSH blob save to downgrade 3GS to 4.1.

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