How to: Easily unroot and return AT&T HTC One M8 back to stock with RUU or Nandroid

The AT&T HTC One M8 is a wonderful smartphone, it’s have gorgeous design and a good software. Not just that, like other HTC devices, an Android development of this phone is also very active, so we’re able to see a lot of custom ROMs and mods available. But with the release of several new smartphones that have a greater ability, you might attracted to upgrade and give your previous phone to others. Before offering your device, it’s better if you unroot and return the AT&T HTC One M8 back to stock condition, because the person who will receive the device won’t need it.

 

Understanding the procedures to restore your AT&T HTC One M8 back to stock is also very useful for you when you encounter problems due to bad flashing or applying incompatible mods that ended in a soft bricked phone. The easiest way to restore our phone is to use an RUU that had been prepared for this purpose, another easy method is to use the stock HTC Sense Nandroid backup.

Main Requirements
  • AT&T HTC One M8 smartphone, already gained S-OFF with Firewater.
  • A Windows computer, only for those who want to run an RUU executable file (*.exe).
  • HTC USB driver latest version, in case you have already installed HTC Sync, remove it from your computer and keep the drivers.
  • Fastboot and adb files and little knowledge about it.
  • Download RUU, stock NANDroid ROM backup for AT&T variants of HTC One M8.
  • The USB debugging option is enabled in phone settings.
at&t htc one m8 back to stock

Image: HTC

1st method: unroot and return AT&T HTC One M8 back to stock with RUU (executable RUU)

Your custom recovery, kernel, firmware, radio will be restored to stock with this RUU.

  1. In some cases, an executable RUU won’t work on unlocked phones, we need to relock it first. You need to put your phone into FASTBOOT USB mode, then run the following command:
    fastboot oem lock

    Additionally, if you have already converted to Google Play Edition (GPE) ROM previously, you also need to revert the CID back to AT&T.

  2. Connect your HTC One M8 to the computer.
  3. Keep your phone into Fastboot USB mode, then run the executable RUU file with administrator right, in this guide we use RUU version 1.58.502.1.
  4. Your phone should recognized by RUU when there’s no drivers issue. In pre-installation process, the RUU will verify your device’s firmware version, then follow any instructions you notice from RUU window.

NOTE: You need to flash custom recovery and Superuser again in order to remove Tampered banner and reset the Relocked banner to Locked.

2nd method: Flash stock HTC Sense Nandroid Backup.

This method is easier because we do not need the help of a computer.

  1. Copy the Nandroid backup (in zip format) into your phone storage.
  2. Boot into custom recovery mode (CWM/TWRP).
  3. Wipe.
  4. Now flash the stock Nandroid.

 

Gain root with SuperSU

This step is required if you want to get rid of Tampered banner and change Unlocked to Locked.

  1. Get flashable SuperSU from Chainfire site.
  2. Copy the SuperSU zip file into the internal storage.
  3. Boot into custom recovery.
  4. Next, flash it
Flash the stock recovery

This should be done if you work with Nandroid method, as we know, flash Nandroid only restore your firmware and kernel, but recovery is still custom.

  1. Get the AT&T HTC One M8 stock recovery.
  2. Move the file into fastboot folder.
  3. Boot into Fastboot USB mode, then run the following command.
    fastboot flash recovery FileName.img
Remove TAMPERED banner from AT&T HTC ONE M8 bootloader

It is quite disturbing as it’s noticeable, found on the top of the bootloader, Tampered banners make your device look broken, though it isn’t. You can get rid of it by running a couple of fastboot commands that you can find here.

Reset the UNLOCKED or RELOCKED bootloader status back to LOCKED

When you unlock the bootloader via the official HTCDev or gain S-OFF, it will show Unlocked on the bootloader, there’s no official way to revert it to Locked. Manually lock your device via fastboot only change it to Relocked. Luckily, we can outsmart it by running the fastboot command described in this post.

Unroot AT&T HTC One M8 with SuperSU

This is required if you want to get rid of root access in your phone.

  1. Open SuperSU app
  2. Go to Settings Tab
  3. Look for Full Unroot
  4. Done

 

Source:xda
Filled Under:Unroot and Relock
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2 Responses

  1. Harlowe
    July 1, 2014 at 11:17 PMReply

    So i tried this but when i run the RUU it fails. And i relocked the bootloader.

  2. mm
    November 11, 2014 at 5:55 AMReply

    Can you pls post a link for the nandroid backup zip file ?

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