The official release dates for Android 5.0 Lollipop update for the OnePlus One were supposed to start today with a OxygenOS ROM and CM 12S ROM in March 30. However it did not happen! Therefore there is available a Android 5.1 Lollipop unofficial ROM.
This ROM is unofficial CyanogenMod which means that CM team is not behind this new ROM. Thus, we have to give credit to xda-developer CraZY-BoY^, that is the person behind this new firmware update.The ROM is based on stock Lollipop 5.1 system and comes with the latest Android features, apps and capabilities along with other dedicated tools that can be found only on the CyanogenMod platform. Also, CM12.1 has been optimized and customized for the OnePlus One device, which means that the software can smoothly run on your smartphone.
In order to intall this custom ROM you have to do a backup of all of your OnePlus One data (contacts, apps, call logs …). After this ou have to root your smartphone.Finally, use the custom recovery image that’s installed on your OnePlus One and make a Nandroid backup. With this if CM12.1 not run properly, you will be able to easily restore the Nandroid backup and downgrade your OnePlus One back to stock Android firmware.
To update OnePlus One to Android 5.1 Lollipop with unofficial CM 12.1 Custom ROM follow this 12 steps:
- First, from this page download the Android 5.1 Lollipop firmware.
- Save the CM12.1 package on your computer, but don’t unzip the file.
- Also, download Google Apps package from here.
- Connect your OnePlus One with your PC by plugging in the USB cable.
- Transfer the downloaded files from your computer, to your smartphone.
- Remove the USB cable and then turn off your phone.
- Reach recovery mode on your OnePlus One.
- From recovery wipe the system and also clear cache by choosing “wipe data factory reset”, “wipe cache partition” and “wipe dalvik cache”.
- Now, return to main menu of recovery and select “install zip from SD card” and “choose zip from SD card”.
- Pick the CM12.1 firmware file and install Android 5.1 on your OnePlus One.
- Then, repeat the same process and install Google Apps package.
- When done, select “reboot system now” from main menu of recovery and enjoy.