There is another potential approach. I used to run Ubuntu for ARM on the same development phone/tablet as Android for the sole reason that I can use the Ubuntu

There is another potential approach. I used to run Ubuntu for ARM on the same development phone/tablet as Android for the sole reason that I can use the Ubuntu/debian tools to debug some Android OS related issue. It is very easy to setup with chroot. MS can probably get linux kernel VM running inside WM ARM cpu. With that, one can probably quickly run Ubuntu or Android unmodified on WM. Pro: probably just work. Google did most of the works already. Android VM runs in x86 Windows/Linux today. Con: Might need more memory. 2+GB for MVP. Not a low end phone anymore Not sure why MS doesn't start with this approach and extend from that.