A new firmware update is seeding for OnePlus One owners with build version YOG4PAS2QL based on Cyanogen OS 12.1. This is not too big an update, but an incremental release, weighing in at 18MB. As the update description suggests, it's a maintenance release incorporating bug fixes and critical security updates.

"I got it a few days ago over ota. Updated it successfully...no error.Works like charm. Battery has improved a lot. The only thing my opo was missing the battery which is back again. Thanks oneplus. Keep this device always updated," reported a member at a OnePlus forum who is among those who have received this incremental version.

The rollout is quite slow though and some 5% OnePlus One owners have received it so far. Nevertheless, those who cannot wait for the stock update to hit their regions, can manually install the latest Cyanogen OS build, as the download links are available for OTA, full zip and even fastboot files. Given below are two different methods. You may choose either of them to install the update depending on the root status of your phone.

Download files for YOG4PAS2QL

OTA zip

Full update

or, Fastboot zip (Alternate link)

Install Cyanogen OS 12.1 build YOG4PAS2QL on OnePlus One [Non-rooted devices]

Step 1: Copy the downloaded files to the phone's storage

Step 2: Switch off your OnePlus One and reboot into recovery mode. Turn on the phone while holding Power and Volume Down buttons together until the phone responds. Within a few seconds you will be presented with the Recovery screen. Select "APPLY UPDATE" from the list of available options

Step 2: On the next screen select "Choose from internal storage"

Step 3: Now select the storage device which should be 0

Step 4: The OTA download file should be located on the Download folder, if you have allowed Chrome to automatically download the file. (If you have chosen a different location follow the appropriate directory to locate the OTA file

Step 5: Select the file then select YES to start installation

Step 6: When the installation is completed, select Restart

How to install Cyanogen OS 12 build YNG1TAS17L on OnePlus One [For rooted devices with TWRP recovery]

Step 1: Reboot your OnePlus One into recovery

Step 2: In the TWRP recovery, select Install

Step 3: Select the downloaded update file

Step 4: Do a swipe on the Swipe to Flash option

Step 5: Select Wipe Cache/Dalvik from the recovery menu

Step 6: Finally select Reboot System

The latest Cyanogen OS 12.1 firmware should be running on your OnePlus One. To know more about the update, head over to OnePlus forum.