Restore iDevices to older firmware

[TangoEight]

Apple, in all of their infinite wisdom, have decided to make it hard to downgrade iOS versions. This makes things awkward when you need to use an older version for jailbreaking or any other reasons that I can't think of. It is possible to downgrade by having SHSH blobs on Saurik's server, but you probably don't and that's why you're reading this guide. This method works by editing some of the files in the .ipsw file that contains the firmware to trick Apple's verification system into thinking that you are restoring to the current firmware.

7zip can be found here:

http://www.7-zip.org/

iPodRobot plist Editor is somewhere over here:

http://download.cnet.com/Plist-Editor/3000-18551_4-10909598.html

You can find .ipsw files here:

http://www.felixbruns.de/iPod/firmware/

Note: This has only been tested on an iPod Touch 2G because that is all I have. This does not work for 3.1.3 (for me anyway). Your mileage may vary.

Other Note:I did not think of this, I found it after updating to 4.1, not liking it and googling for a way to fix it.

Even more notes: Click the images to enlarge.

1. Download the ipsw file you will be restoring to an put it somewhere on your computer.

2. Make all file extensions visible.

Press the Alt key and select Tools>Folder Options...

Got to the View tab and uncheck Hide extensions for known file types. Apply and close.

3.Make a new folder and copy the .ipsw into it so you have two copies with the same filename.

4. Rename the file to a .zip.

Rename it changing only the extension to .zip.

Because you are changing the file type you will get a warning, click Yes.

5. Open the .zip and copy the BuildManifest.plist and Restore.plist files into the folder with your .ipsw file.

6. open the .plist files with iPodRobot.

Find and replace the original build number with the build number of the latest firmware for your device. It should appear twice or three times in BuildManifest.plist and once in Restore.plist.

The build number is in the file name and next to the device name on the list here.

The file name should be in this format:

ipod2,1_4.0_8A293_Restore.ipsw
"device name"_"version number"_"build number"_Restore.ipsw

7. Create the modified firmware.

Delete the BuildManifest.plist and Restore.plist files from the .zip file and copy in your modified .plist files in their place. Rename the zip file into an .ipsw file like in step 4.

8. Finishing.

If you prefer to hide extensions repeat step 2, checking the box.

Open iTunes and connect your iDevice shift click the Restore button and select your modified firmware. From here, continue the restore as normal.

If you get a 1394 error, you are using the wrong build number, try older build numbers, 8B117 seems to work on iPod Touch 2G (as of January 2011).

T8

[UN1X]

Thanks alot for posting a link to this topic, I have a 4G iPod Touch and ill let you know how it goes.

I will also post if jailbreaking works using this method.

[UN1X]

I tried using the method but I keep getting a 3194 error.

I have 4.2.1 on a 4G iTouch and I'm trying to get down to 4.1. I have edited the firmware, but it doesn't seem to be tricking the apple servers.

Do I have to edit the file name to match the new firmware as well?

I guess it's no luck for 4G 4.2.1ers as of now?

[TangoEight]

  On 02/02/2011 at 15:19, UN1X said:

I tried using the method but I keep getting a 3194 error.

I have 4.2.1 on a 4G iTouch and I'm trying to get down to 4.1. I have edited the firmware, but it doesn't seem to be tricking the apple servers.

Do I have to edit the file name to match the new firmware as well?

I guess it's no luck for 4G 4.2.1ers as of now?

3194 is the one I meant at the end of the first post. I think it means the build number you used is for an older firmware which they don't want you using anymore or its for a different device.

The latest build number for your iPod (4G) is 8C148. The example I used was for a 2G.

T8

[UN1X]

  On 03/02/2011 at 01:00, TangoEight said:

3194 is the one I meant at the end of the first post. I think it means the build number you used is for an older firmware which they don't want you using anymore or its for a different device.

The latest build number for your iPod (4G) is 8C148. The example I used was for a 2G.

T8

I used 8C148.

It gave me 3194.

I've even tried doing it with tinyumbrella in a separate tutorial. No success.

[Dinggus]

  On 02/02/2011 at 15:19, UN1X said:

I tried using the method but I keep getting a 3194 error.

I have 4.2.1 on a 4G iTouch and I'm trying to get down to 4.1. I have edited the firmware, but it doesn't seem to be tricking the apple servers.

Do I have to edit the file name to match the new firmware as well?

I guess it's no luck for 4G 4.2.1ers as of now?

Try TinyUmbrella, it'll "kill" the process to connecting to Apple Servers.

[TangoEight]

The build number for 4.1 worked for me but it probably won't work for restoring to 4.1. I don't know what else to suggest. Tiny umbrella won't work by itself because you need apple to verify the restore, iTunes needs to receive the "OK" message from apple or it will give you the 3194 error.

T8

[TangoEight]

  On 02/02/2011 at 15:19, UN1X said:

I tried using the method but I keep getting a 3194 error.

I have 4.2.1 on a 4G iTouch and I'm trying to get down to 4.1. I have edited the firmware, but it doesn't seem to be tricking the apple servers.

Do I have to edit the file name to match the new firmware as well?

I guess it's no luck for 4G 4.2.1ers as of now?

Just thought, did you edit the restore.plist file too, I didn't include a picture for that one and didn't make it that clear.

I had a go at doing it for your ipod, will link to the file when it uploads so you can test it, these retina graphics make it a huge file :/

T8

[Tech Star]

I might try this. I am on 4.0 with my iPod Touch 2G and I just hate the battery life now. I have wanted to go back to 3.1.3.

[Brandon H Supervisor]

it seems that if you buy an ipod 4g that already has 4.2.1 on it there is no way to downgrade it to 4.1,

not really sure what they changed but it can not be done

if you've upgraded to 4.2.1 you can downgrade back to 4.1 but not if the ipod's only had 4.2.1 for whatever reason

[Brandon H Supervisor]

  On 03/02/2011 at 19:56, TangoEight said:

Just thought, did you edit the restore.plist file too, I didn't include a picture for that one and didn't make it that clear.

I had a go at doing it for your ipod, will link to the file when it uploads so you can test it, these retina graphics make it a huge file :/

T8

can you send me a link too, i'm trying to get my friends new ipod downgraded so he can jailbreak it, if it doesn't work i guess we'll just have to wait till greenpois0n's 4.2.1 jailbreak is released :/

[TangoEight]

  On 02/02/2011 at 15:19, UN1X said:

I tried using the method but I keep getting a 3194 error.

I have 4.2.1 on a 4G iTouch and I'm trying to get down to 4.1. I have edited the firmware, but it doesn't seem to be tricking the apple servers.

Do I have to edit the file name to match the new firmware as well?

I guess it's no luck for 4G 4.2.1ers as of now?

The whole ipsw isn't going anywhere on my connection :no: but here are the files you will need to move into the ipsw replacing the existing copies.

BuildManifest.plist

Restore.plist

iPod touch 4g restoring down to 4.1 ONLY

T8

[Brandon H Supervisor]

  On 03/02/2011 at 21:56, TangoEight said:

The whole ipsw isn't going anywhere on my connection :no: but here are the files you will need to move into the ipsw replacing the existing copies.

BuildManifest.plist

Restore.plist

iPod touch 4g restoring down to 4.1 ONLY

T8

you put the same link for both files

[TangoEight]

  On 03/02/2011 at 22:22, Brando212 said:

you put the same link for both files

Sorry about that.

Restore.plist

http://www.box.net/shared/koxtvf5a68

T8

[Brandon H Supervisor]

sadly i still get the same error :(

[TangoEight]

Apple might have increased security for newer iPods. Not sure if there is any other way to restore down other than with SHSH blobs but I think you need jailbreak for them.

Will post if I find anything.

T8

[TangoEight]

Got some good news for you, Greenpois0n has been released for iOS 4.2.1

http://lifehacker.com/5752219/greenpois0n-brings-a-long+awaited-untethered-jailbreak-to-ios-421

Tried to look in the .dmg files in the .ipsw but they're encrypted :(

T8

[Brandon H Supervisor]

awesome, just in time to give the ipod back to my friend tomorrow

that was the whole reason for trying to downgrade it was so i could jailbreak it

crap, just realized it's only released for osx right now :/

if i'm lucky i'll be able to log onto one of the macs at school tomorrow and do it from there