What is the latest iPhone OS/Firmware that I can unlock?

Discussion in 'Jailbreaks and iOS Hacks' started by ayasinsk, Apr 17, 2010.

  1. ayasinsk macrumors regular

    Apr 29, 2008
    I'm trying to buy an iPhone on craigslist and then unlock it. What is the latest iPhone OS/firmware combo that I can unlock the phone with? I know that 3.1.3 and Firmware 5... is a no go, but 3.1.2 with Firmware 5... is good? How about 3.1.3 with old Firmware 3...., can I downgrade in that case? Thanks.
  2. Applejuiced macrumors Westmere


    Apr 16, 2008
    At the iPhone hacks section.
    3.1.2 is the last firmware you can unlock.
    Once its updated to official 3.1.3 the baseband is also updated and that cannot be undone or downgraded in order to be unlocked.
    So you're looking for baseband 05.11.07 NOT the latest one 05.12.01

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