clarification for a newbie please

Discussion in 'iPhone' started by jdlindsey7, Mar 3, 2010.

  1. jdlindsey7 macrumors regular

    Feb 4, 2010
    I've read myself silly trying to understand this, so I'm really hoping someone can help clear this up for me. I'm looking for an iPhone to use on T-Mobile, so unlocked. I was told by someone to look for an iPhone that is 3.1.2 or earlier firmware. Then, I've been told by someone else I need to look at the modem firmware and make sure it is not 05.12.01. So if someone has a 3GS that is 3.1.2 but 05.12.01 does that mean it cannot be unlocked? How would a phone get the updated modem firmware 05.12.01 but still be on 3.1.2? Thanks for your help.
  2. thelatinist macrumors 603


    Aug 15, 2009
    Connecticut, USA
    If you have a 3GS with 5.12.01 and 3.1.2, that means your phone was upgraded to 3.1.3 and then downgraded using a cached signature hash. Such a phone can be jailbroken but, sadly, is no longer unlockable.

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