The just launched flagship OnePlus 3 is a fully developer friendly device. It is easy to unlock its bootloader, which means you can install custom recovery like TWRP and gain root access on the device (thanks to the extended support by OnePlus team). These two are main things for device development. Now, OnePlus 3 stock Oxygen OS ROM is available for download that you can use to restore your device to stock.
OnePlus’s Oxygen OS v3.1.2 ROM for OnePlus 3 is now available for download. The recovery flashable full stock ROM (signed zip) will not overwrite your data partition. You can use the ROM to unbrick or unroot your OnePlus 3. In this guide, we will show you how to install stock Oxygen OS v 3.1.2 ROM on OnePlus 3.
For your information, OnePlus 3 is running on the Android 6.0.1 Marshmallow under the Oxygen OS skin. Oxygen OS lets you fully customize your device with different accent colors and icon packs. Also, it provides various gestures to help using the phone lot easier.
Disclaimer: The below procedure will void your device warranty. Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components.
Important: Backup important files you have on the phone before proceeding with below steps.
2. Save the downloaded ROM zip file on your phone
3. Next, reboot OnePlus 3 into recovery mode. To do so, switch off the phone, the press and hold Volume Down + Power button together until you see anything on screen.
4. In recovery, choose ‘Install from local’, select the ROM zip file, and confirm the installation.
The ROM will be installed automatically. Once done, restart the device. The first boot will take few minutes. (Source – OnePlus)