Inside the app, scroll down to theFull Unrootoption to begin the process.
This will erase any trace of your machine ever being rooted.
First thing you will need, is the factory image of your machine on your rig.XDAis a great resource.
Unzip the file that you have downloaded.
Switch back to your system.
Copy theboot.imgin the folder you unzipped and place it in your ADB folder C:android-sdk.
Next, connect you phone to your setup via USB and open a command prompt on your PC.
Look for an update underSettings>About machine.
Just be careful when you proceed with this as it might not work with every rig.
source: www.techworm.net
