Quoting http://www.ubuntu.com/devices/phone/operators-and-oems :

> Ubuntu has already been adapted to run on chipsets using the ARM and Intel x86 architectures relevant for mobile devices, with the core system based around a typical Android Board Support Package (BSP). So chipset vendors and hardware manufacturers do not need to invest in or maintain new hardware support packages for Ubuntu on smartphones. In short, if you already make handsets that run Android, the work needed to adopt Ubuntu will be trivial.