CODEWITHSUNDEEP
iphone
dizy
dizy

Reputation: 7959

iphone firmware downgrade

I'm trying to downgrade my firmware to 3.0 so that I can test compatibility of my app. I tried doing an Option+Restore in itunes and selected iPhone1,2_3.0_7A341_Restore.ipsw I found on the web, but it errors out about half way through.

When I tried downgrading from xcode organizer I got an "Error: Updating baseband: The baseband cannot be rolled back"

Is there anyway to roll back the firmware ?

Upvotes: 0

Views: 2205

Answers (3)

Jason B
Jason B

Reputation: 665

If your baseband has been flashed, you can't do anything. If it hasn't, however, entering DFU mode will make your life a lot easier:

  1. Turn off the phone while connected to the computer
  2. Hold down the power & home buttons for 10 seconds
  3. Release the power button; continue holding the home button until iTunes recognizes that the phone is there
  4. Try to downgrade again

If you get the same error, your baseband has been upgraded, and you're out of luck.

Upvotes: 0

Bryan Henry
Bryan Henry

Reputation: 8408

While Jasarien is correct in that you cannot rollback the baseband once a device has been flashed with a specific baseband (in the general case, anyway), you can still usually downgrade the firmware. This will, however, not downgrade the baseband and unless the newer baseband is compatible with the old firmware (unlikely) you'll be left with a device that cannot connect to the cellular network or perform other networking functions, possibly including not being able to connect to a Wifi network. If a lack of networking capability would leave you unable to test your application, then you will need to find someone who still has a device on 3.0. Additionally, Apple has Compatibility Labs if you are near their Cupertino campus.

If you do still want to roll back the firmware, you can do so, but you'll be greeted with an error number (probably error 1015). This in itself isn't a problem - this just signifies that the baseband flashing failed - but you'll need to use some third-party software to kick your iPhone out of restore mode.

Unfortunately, if your device is a iPhone 3GS, you're out of luck. Apple stopped signing firmware updates for 3.0 and 3.0.1 quite a while ago, and unless you prepared ahead of time to ensure that you could retain your ability to downgrade to 3.0 (which sounds unlikely, if you're asking this question), you're up a creek.

If you need more detailed downgrading instructions, I suggest you take a look at one of the many blogs with instructions (a small sampling of which are listed): http://www.iphonedownloadblog.com/2009/09/15/downgrade-iphone-31-to-30/ http://www.blogsdna.com/3911/how-to-downgrade-iphone-3gs-31-to-30-os.htm

Upvotes: 1

Jasarien
Jasarien

Reputation: 58448

Once the baseband is flashed to a particular version, you can't downgrade it. It's a permanent flash.

You'll have to find someone who has a 3.0 device and send them an ad hoc build to test. If you buy a new device it'll come with the latest firmware, so finding someone who hasn't upgraded is your only option.

Upvotes: 0

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