OnePlus released a stock version of Android 4.4.4 for the OnePlus One for those not comfortable enough with the built-in CyanogenMod 11S ROM. This new Android Kitkat AOSP ROM aims to bring a 100% pure Android experience and widens the configuration possibilities of one of the most versatile devices on the market.
- First, you need to download the ROM
- Then you should download Google Apps, as they're not in the ROM
- Flash the downloaded ROM .zip file onto your device
- Unlock the boot loader and custom recovery
- Reboot your device into recovery mode
- Wipe your device and clear the cache
- Install the .zip file from the custom ROM
- Install the .zip file from the Gapps
Flashing this ROM does not void your warranty, but if you brick your phone you'll have to contact Oneplus for repair —at a cost. Also note this is a work-in-progress ROM and some minor things might not work as expected.
Source: OnePlus Forum