OnePlus One
Guide to restore stock firmware on OnePlus One.CyangenMod

If you have unlocked the bootloader of OnePlus One to gain complete control of the device via root access, you can still revert to stock firmware and reset the phone to its 'out-of-box' status.

XDA contributor, EddyOS has shared a tutorial to restore CyanogenMod 11S based stock firmware on OnePlus One. Besides, this will lock bootloader and run the latest CyanogenMod 11S firmware with XNPH33R build. Head over to the development thread to know more.

The developer further states, "It's recommended that you have adb/fastboot in your System Path. This makes it easier to run commands as you don't always have to 'in' your adb/fastboot folder to run the commands."

Interested users, who wish to return to stock firmware on OnePlus One, may follow the guide below.

IBTimes UK reminds its readers that it will not be held liable for any damage to the device.

Points to remember

  • Ensure the OnePlus One has above 80% charge to avoid unusual shut down during the process.
  • Back up all the data of the device before following the restore guide.
  • The bootloader of the phone should be unlocked.

How to restore OnePlus One to stock firmware

Step-1: Download stock firmware for OnePlus One according to the model of the device (Either for 16GB or 64GB)

Download links:

XNPH33R 16GB: cm-11.0-XNPH33R-bacon-signed-fastboot_16GB.zip

XNPH33R 64GB: cm-11.0-XNPH33R-bacon-signed-fastboot_64GB.zip

Step-2: Download ADB/fastboot files then extract them to a folder on your PC

Step-3: Extract the firmware files to a similar folder where the ADB/Fastboot files are

Step-4: You should see files such as flash-all.bat (Windows) or, flash-all.sh (Linux). These are 1-Click installers for the firmware files

Step-5: Reboot the OnePlus One to Fastboot mode and connect it to the computer. Click the 1-Click installer files according to the OS of the computer

Step-6: The flashing process will start automatically and once it is complete, the phone will reboot

Reset the tamper flag/lock the bootloader

There is a flag/bit on the phone, which is triggered when the bootloader is unlocked. Relocking it will not change the flag back to normal. Using the method below you can restore these bits.

Step-1: Enter into recovery mode on the OnePlus One

Step-2: Download Boot unlocker script, install it using recovery

Download link: OnePlusOne-BootUnlocker.zip

Step-3: When the flashing process is completed, reboot the phone

The OnePlus One should now be running on stock XNPH33R build.

[Source: DroidViews]