My OnePlus One is blank except for my custom recovery(TWRP). Can I download an OnePlus One Ubuntu Image, transfer via USB, and flash it through custom recovery like you would with Custom Android ROMs?
@14v3nd3r No sorry in short it does not work like that. You need to use the installer. The UT recovery is flashed first using fastboot then the device goes to recovery to push the files to the device.