I upgraded my Swift 2x to Android 8.2, however this resulted in very poor battery life.

Frustrated with this, I looked around to see if I could restore the original factory ROM and revert to Android 7.x

So here are the steps I took to achieve this.

NOTE: Please read this guide thoroughly from start to finish before attempting any of the steps - and additionally, ensure you are comfortable with doing this - one mistake could leave you with a non functional* phone.

WARNING: The following steps will erase all data off your phone. Please ensure you have backed up any important data before attempting these steps.

Download SDK Platform Tools (adb)

Extract the .zip file into a folder of your choice (I use c:\adb)

Download and install Android drivers (on your PC)

Download the factory ROM from here

Or a local download here

Extract the contents of the factory ROM to your adb folder as per above (in my case c:\adb)

Open a DOS prompt in 'Administrator mode' and change to the folder where you unzipped the Platform Tools (c:\adb)

Now return to your phone and:

Enable developer mode:
Go to "Settings", "About Phone" and tap "Build Number" 7 times.

Once you have enabled "Developer mode" go into developer options and enable:




Plug the phone into USB (I had to use a USB2 port on my PC for some reason) and then connect to the phone using ADB.

Check if the phone is present:


This should return a device code.

Note:
At some stage during the above, you will be prompted to authorise the PC to connect to the phone (on the phone)

Reboot into bootloader:


Unlock boot loader:


Flash new boot image:


Flash recovery image:


Flash system image:


Reboot into bootloader:


Lock bootloader:


Return to developer options and disable: (this step is optional but recommended)




Following the installation of this ROM, you will be prompted with further updates to bring the phone up to "1 January 2018" "Android security patch level"

You will also be prompted for a "System Update" which will attempt to update the phone to Android 8.2 again - you need to disable this update by disabling the "System update service" in "Apps and Info".

Following all the updates, my phone ended up back at:
Android 7.1.2
Build number: TOS373J-N2G48B

*Disclaimer:
I cannot be held responsible if you should 'brick' your phone or damage it any way using the above process.




Tags: Android , phone

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