On a Xiaomi Mi2S with 4.1.1 JRO03L version, MIUI Version MIUI-JLB21.0. Installing GooglePlay was very easy. Downloading and installing apps worked as well very smoothly, but suddenly my phone started to crash - every app I've opened was closed just after few seconds. Nasty thing. Here is what I've discovered; After downloading and logging in to the Google account, if the phone is restarted it becomes unstable, the only way to solve the problem is to restore it to the factory settings and reinstall all apps again. As long as the Google account is not connected, everything works perfectly.