Mr Longchivas from Vietnam has public the guide to install Global ROM for 19AA
http://miui.vn/forum/threads/cai-dat-fir…-aa.50835/
I have tried it myself and confirm it works as expected.
Could be useful for those who bought the wrong box and still stuck in Chinese UI.
Plus, after flash to Global version, it can auto update to latest google security patch.
looks like it can also update to android 7.0 beta test ROM for global version, not try that yet.