There are the steps to install Oxygen Os on OnePlus One:
- Download OxygenOS HERE
- On your device, go into Settings -> About and find the Build Number and tap on it 7 times to enable developer settings. Press back and go into Developer Options and enable USB debugging
- From your computer, open a command prompt and type:
adb reboot bootloader
- Unlock the device:
fastboot oem unlock(You can skip this step if your phone’s bootloader is already unlocked)
- Download latest recovery image from HERE
- Run the following command:
fastboot flash recovery twrp.img
- Reboot the phone by:
- Unzip oxygenos_1.0.0.zip. In there, you will see a oxygenos_1.0.0.flashable.zip file. Copy oxygenos_1.0.0.flashable.zip to your phone. You can use Android File Transfer.
- Boot into recovery. You can do this on your OnePlus One by holding down both the volume down key and the power button.
- Once you are in the recovery interface, the first thing you want to do is a factory reset. Again, you will lose all your data so please make sure you have backed up everything before doing this.
- After the wipe, go to install and find oxygenos_1.0.0.flashable.zip. Confirm flash. This will flash OxygenOS onto your device.
- After the flash succeeds, you can reboot the device, which will take you to the new OxygenOS. Enjoy!