After several months of hypes, Cyanogen OS 12S (Android 5.0 Lollipop) is finally here for all OnePlus One smartphone users. The OTA (over the air) update is currently rolling out and you will get the OTA notification soon on your device. You can check the update on your device by going to Setting -> About Phone.
While the developer of OnePlus One has already released the Android 5.0.2 Lollipop based ROM, dubbed OxygenOS for OnePlus One, the Cyanogen OS 12S brings all the Lollipop features along with sweet additions like App Themer, Cyanogen email powered by Boxer and full Material Design UI.
OnePlus One users who are running on stock CyanogenMod 11S ROM will receive the OTA update soon. If you are not received the update notification, go to phone Settings -> About Phone and check for a software update. It will take some times to reach the update.
Users who cannot wait for the OTA update can install the update manually. A Reddit user capture the official OTA update ZIP file and share it with the OnePlus family. Interested users can download the firmware and manually flash CyanogenMod 12S OTA ZIP on your phone.
1. Download Cyanogen OS 12S OTA zip file (cm-12.0-YNG1TAS0YL-bacon-signed.zip) [HERE] and move it to internal memory.
2. Enable USB Debugging on your phone by going to Settings -> Developer Options
3. Install custom recovery like TWRP or CWM
4. Boot your phone into recovery mode. To do so, switch off your phone, hold down the Volume up +Volume down buttons at the same time.
5. From recovery, wipe cache, dalvik cache and data (It will prevent any possible errors while updating).
6. Now, go “Update from file” and chose the CyanogenMod 12S OTA ZIP file.
7. Once done, reboot your phone. (Source – Reddit)