Few days back (as of the time of updating this post), Cyanogen team released CM 12.1 (Android 5.1.1 Lollipop) for OnePlus One, and this update can be done over-the-air OTA, but the OTA update haven’t been pushed to all OnePlus One device. However, if you’ve not receive the update via notification, then this guide would help.
Step 2: After that, download CM 12.1 from here, and move the downloaded files to the internal storage of your OnePlus One device.
Step 3: Now, boot your OnePlus to recovery mode.
Step 4: Once you get to the recovery mode, simply perform a full system wipe (Wipe Data/Factory Reset, Wipe Cache Partition and then Wipe Dalvik Cache/ART cache from advanced section).
Step 5: After that, go to the recover main menu, then select install, then select the CM 12.1 Zip file and install immediately.
Step 6: Once the installation process is completed, simply go back main recovery menu and tap on Reboot system, and your device would be rebooted.
That’s it. You would begin to experience Cyanogen OS 12.1 on your OnePlus One device.
In this guide, I would walk you through the process on how to manually upgrade your OnePlus one smartphone to CM 12.1.
How to Install Official CM 12.1 (Android 5.1.1 Lollipop) on OnePlus One
Before proceeding to the below guide, make sure that your Oneplus One have the latest custom recovery (TWRP/CWM) installed on it. If not, check how to install latest custom recovery on OnePlus One.
Step 1: Enable USB debugging on OnePlus One, simply go to settings >> Developers option. If the developers option isn’t visible on your device, simple go to “About Phone” under settings, then scroll to “Build number” and tap up to seven times to make the developers option visible.
Step 1: Enable USB debugging on OnePlus One, simply go to settings >> Developers option. If the developers option isn’t visible on your device, simple go to “About Phone” under settings, then scroll to “Build number” and tap up to seven times to make the developers option visible.
Step 2: After that, download CM 12.1 from here, and move the downloaded files to the internal storage of your OnePlus One device.
Step 3: Now, boot your OnePlus to recovery mode.
Step 4: Once you get to the recovery mode, simply perform a full system wipe (Wipe Data/Factory Reset, Wipe Cache Partition and then Wipe Dalvik Cache/ART cache from advanced section).
Step 5: After that, go to the recover main menu, then select install, then select the CM 12.1 Zip file and install immediately.
Step 6: Once the installation process is completed, simply go back main recovery menu and tap on Reboot system, and your device would be rebooted.
That’s it. You would begin to experience Cyanogen OS 12.1 on your OnePlus One device.