I am with a spare TV-Box MXQ Pro 4k here at home. It comes with an old version of Android 7.0, with some stuff bundled (Youtube, file manager etc.).
Also, I successfully ran EmuELEC on it, via dd-flashing an SD card plus toothpick rebooting.
What I need to know and to do in order to build an SD Card with NixOS for it?
I plan to document all the process, from the cross-compilation toolchain to a bootable image containing some basic stuff like a web browser and a video player… and an Emacs!