Cyanogen team has released Cyanogen OS 12.1 (Android 5.1.1 Lollipop) for Yu Yureka and Yu Yureka Plus. Users will receive the OTA (over the air) update on their device in the coming weeks. If you are impatient to wait for the new update or if you have not received the update notification for some reasons, you can manually install the Cyanogen OS 12.1 update right now.
In this guide, we let you know how to flash Cyanogen OS 12.1 firmware (YOG4PAS3JM) on Yu Yureka/Yu Yureka Plus manually. This installation method requires stock recovery (not TWRP) on your device, which means your device should not be modified. Also, your Yu Yureka updated to Cyanogen OS 12 (YNG1TAS34J).
Note: Though this update does not wipe your device, it is highly recommended that you should back up every data on your phone before proceeding.
Disclaimer: Follow the guide carefully and at your own risk. We will not take any responsibility if anything went wrong. This guide is intended only for technically talented users.
1. Download Cyanogen OS 12.1 (674MB) [HERE] (cm-12.1-YOG4PAS3JM-tomato-signed.zip) and transfer the update zip file to your phone’s internal storage.
2. Now, boot your Yureka into recovery mode. To do so:
Go to Settings -> About phone -> tap on the Build Number seven times to unlock Developer Options. Now go to Settings -> Developer Options -> enable ‘Advanced Reboot’ option. Now long press the power button, select the reboot option and select reboot to recovery option.
3. From recovery, select Apply update -> Choose from Internal Storage -> 0/ -> select the zip file you transferred in step 1 above.
4. Once you select the file, the recovery will start flashing the update. When the update completed, you will be back on the main recovery menu.
5. Select the Reboot system now option and wait for the reboot process to complete.
Enjoy Android 5.1.1 Lollipop + Cyanogen features on your Yu Yureka or Yu Yureka Plus (Source)