Hello, I bought a Mi box 4 in China and brought it to the US couple months ago and it's just been sitting there since the first time I turned it on because everything is in Chinese.
I recently found out that they released the exact same device but in Black and Netflix and google voice button on the remote and named it as Mi Box S as an international model.
Will it ever be possible for Mi Box 4 users to install the same firmware from Mi Box S? (Android TV)
TL;DR
NO!!!
Best you could is to semi uncripple it by setting menus to English as in this link
http://en.miui.com/thread-391907-1-1.html
Still pretty much useless as lacks DRM and codecs to play much western streaming content