If it's the exact same hardware components, then it might work.

It's really doubtful it'd work. ARM is not x86; even if the processor is exactly the same, there are no standards for what surrounds it, so roms pretty much have to be specifically designed for each and every device. That said, it might be possible for someone to put together a rom that spoofs the MiBox's keys for the purposes of things like DRM. I don't know if there's the kind of development community around that box that could do that, though.

You can get the android tv launcher to work on an s90x box, not sure if it was the offical or a copy though. But drm et al won't work.