To be on a safer side, before you start to forge ahead in unrooting your rooted device (Android), make sure to do the following first:
==>Backup your data: Reason is because, while unrooting the device, all your data will be wiped out. So to avoid that, make sure to backup all your data either on your SD card or backup on your PC.
==>Charge your Android: Make sure the phone battery is charged more than 60% in order to get a better result when rebooting the device.
THE FIRST METHOD: SUPER SU APP
This particular method works on all Android mobile that were rooted without the install of custom recovery.
==>Step 1. First, you need to download and install SuperSU app from Play Store.
==>Step 2. Launch the SuperSU application, then go to its Settings, and click on where you see “Full unroot”.
==>Step 3. the app will confirm that and next, just click continue. After you must have done that, now Unroot superuser, it will close automatically by it self.
==>Step 4. Go ahead and restart your device
==>Step 5. After restarting, Uninstall SuperSU app and you will see that your device is fully and successfully unrooted. That’s all for the first method.
FOR SECOND METHOD: ES FILE EXPLORER
==>Step 1. If you don’t have ES File Explorer app on your device go to play store and download, install it. Take note, don’t move it to SD card. And if it is installed on SD card, just move it to internal storage.
==>Step 2. Open the ES File Explorer app and click on the menu button
==>Step 3. Locate and click on “Tools” and now choose “Root Explorer” in order to turn it on.
==>Step 4. Superuser app will ask you for a permission to grant root privilege to the app. Approve it.
==>Step 5. Next, is to go back to the main menu screen of the app and select this ‘/’ on the top corner of the screen.
==>Step 6. Now go to system >> bin. In bin, Find what is called busybox and su file there and remove by deleting them. Notice: If you can’t find or see any of them there to delete, just go to the next step below.
==>Step 7. To locate busybox and Su which is not seen in step 6, just go back to system folder and then open “xbin” folder and here you will see busybox and su file then delete them (if you found any).
==>Step 8. You will need to go back to the system folder again and then open “app” folder, and also delete the supeuser.apk file which is located in the folder there. We are almost done with the process as only one step is remaining. Which is,
==>Step 9. A must thing to do, now restart your Android device and with the successful application of the steps above, your device should be unrooted now.
You can now proceed to system update/upgrade or any other thing that reuires your device to be unrooted before application.