Can an unsuccessfully unlocked iPhone 3G work with AT&T again?

Discussion in 'Jailbreaks and iOS Hacks' started by dracula123, Feb 6, 2010.

  1. dracula123 macrumors newbie

    Feb 6, 2010
    I've just bought an iPhone 3G 8G. However the seller has upgrade OS to 3.1.3 so that the firmware is 05.12.01 now.

    I could downgrade to 3.1.2 and jailbreak it. However, I could not downgrade firmware to 05.11.xx. Now my iPhone can access Internet but making phone call. There always be "No service" message at the network bars.

    If I change my plan to AT&T, will my iPhone work with AT&T even it was unlocked unsuccessfully?

    What should I do to make it work with AT&T.

    Thank you.
  2. dhlizard macrumors G4


    Mar 16, 2009
    The Jailbreak Community
    The firmware (but not baseband) on the 3G phone can be upgraded or downgraded as wished. It can be jailbroken at any firmware version, but since it has the new 5.21.xx baseband it cannot currently be unlocked.

    If it is one of the very early 3G phones and you jailbreak it, you can try Fuzzyband thru Cydia. Fuzzyband has been able to downgrade the baseband of about 10% of the very early 3G phones.

    Yes, the phone can be used on AT&T either JB or not JB at any firmware version.

    Go to the DevTeam Blog (Google it) for tools and instructions on how to downgrade your 3G from 3.1.3 if needed.
  3. dracula123 thread starter macrumors newbie

    Feb 6, 2010
    Thank you.
  4. Applejuiced macrumors Westmere


    Apr 16, 2008
    At the iPhone hacks section.
    Yes, a us iPhone will always work with any AT&T simcard no matter if it's jailbroken or on stock firmware.

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