Downgrade iOS 11.3 / 10.3.3 to 11.1.2 / 10.1.1 - Without SHSH - iPhone, iPad, iPod

Apple never allows you to downgrade iOS on iDevices, that's the major problem faced by many users as we know that latest version of iOS is not the greatest as it slows down old devices and also destroys jailbreak. iPhone 4 became almost unusable after iOS 7 update and iPhone 5 and 4S faced noticeable lags which are very annoying. We all know that iOS 6 and iOS 5 were lightning fast but apple don't want us to be happy.

But don't worry you can downgrade to previous version of iOS without even need of SHSH Blobs and AP Tickets.

IPSW tool generates ECID-SHSH blobs using UDID and ECID info fetched from the device and generates a patched .ipsw which fakes the firmware verification process and restores your device to previous baseband. iPhone 4 users can now downgrade their device to iOS 6.1.3 or 5.1.1 WITHOUT SHSH BLOBS.

Usins IPSW Tool you can downgrade the following devices without shsh blobs:

[A4]iPhone 4: [iOS 7.1.2 to 6.1.3] [iOS 7.1.2 to 5.1.1]
[A5]iPhone 4S: [iOS 9.3.5 to 8.4] [iOS 9.3.5/8.4.1 to 6.1.3] [iOS 9.3.2/8.4.1 to 5.1.1]
[A6]iPhone 5: [iOS 10.3.2 to 10.2/9.3.3/7.1.2] [iOS 10.2/8.4.1 to 6.1.4]
[A7]iPhone 5S: [iOS 11.3 to10.2/9.3.3/11.1.2]
[A7]iPhone 5C: [iOS 10.3.2 to10.2/9.3.3]
[A8]iPhone 6: [iOS 11.3 to 10.2/9.3.3/11.1.2]
[A8]iPhone 6+: [iOS 11.3 to 10.2/9.3.3/11.1.2]
[A9]iPhone 6S [11.3 to 10.2/9.3.3/11.1.2]
[A9]iPhone 6S Plus [11.3 to 10.2/9.3.3/11.1.2]
[A10]iPhone 7 [10.3.2 to 11.1.2]
[A10]iPhone 7 Plus [11.3 to 11.1.2]
[A11]iPhone 8 [11.3 to 11.1.2]
[A11]iPhone 8 Plus [11.3 to 11.1.2]
[A11]iPhone X [11.3 to 11.1.2]

[Also applies to same corresponding iPod and iPad Chip. ]

iPSW tool supports Apple A4, A5, A6, A7 and A8 devices, however you cannot downgrade to any version of iOS 6 on A7/A8 devices but still you can switch to any version of iOS 7 on these devices.

[UPDATE: [02/07/15]
Note: A8 Devices ie: iPhone 6, iPhone 6 Plus, iPad Air 2 only supports iOS 8/iOS 9 downgrades due to it's baseband version.

Here is how:
Connect your device and start iPSW tool. Make sure you are connected to internet.
Note: Please make backup of your device before proceeding to restore process. 

Extract and open iPSW Tool

Select your iOS version.

Select iOS version to which you want to downgrade.

Select your device platform ie: Chip model.

Select an iOS firmware file (.ipsw) to sign.

Click on "Patch" to sign your device firmware (it will take a while).

Now simply put your device in DFU mode and start itunes, restore the patched .ipsw by clicking on restore (holding shift key) and it will start installing iOS firmware without any errors.

Note: If your restore stuck with itunes error_xxxx then check your host file, make sure it does not contain any bad host entry which usually blocks the restore.

After restoring firmware, your device will take a while to boot for repairing disk permissions and installing kernel cache.

NOTE: In this tutorial we have shown how to downgrade from 8.4.1 to 6.1.4, you can also downgrade iOS 11.3 to 11.1.2 on supported devices.
                                                                      

Version 3.1

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[Update 10/15/16]

Some users reported that restore is not working in new version of iTunes 12.x.x and later.

[Fix]

Make backup of these files 

MobileDevice.dll

iTunesMobileDevice.dll

AppleMobileDeviceService_main.dll  in

C:\Program Files (x86)\Common Files\Apple\Mobile Device Support  [64bit Users]

C:\Program Files\Common Files\Apple\Mobile Device Support  [32bit Users]

and replace them with these files. After replacing these files, patch your firmware with iPSW tool and restore it with iTunes without the error: 200x.


Note: This update applies only if you are downgrading to iOS 5.1.1 and 6.1.3/4

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