For those of you who want to unroot, you can easily do this on the Galaxy S6 or S6 Edge by simply reflashing stock firmware using ODIN program. This would be ideal for those of you who want to reinstall stock firmware on your phone, maybe need to return phone for warranty purposes, or perhaps selling your phone on eBay or Craigslist. Also, maybe you ended up in a nasty bootloop and you want to restore your phone.
Whatever the reason is, it’s simple to do, so let me show you how to unroot/unbrick you Galaxy S6 or S6 Edge completely back to stock.
Step 1. Go to Settings->About and find the model number of your Galaxy S6 or S6 Edge. On mine, it says “SM-G920T”. Make a note of it as we will download the appropriate stock firmware for that model.
Step 2. Power off your phone then hold down Volume Down, Center Home, and Power buttons together until you see the warning screen like below:
Step 3. Hit Volume Up button once to enter ODIN download mode and connect a micro-USB cable from your S6 or S6 Edge to your computer.