What it is

Xiaomi SIM Activation Service

SIM authentication process to access exclusive features in certain MIUI applications.

For the activation to work you need to send a international SMS to China.

Your carrier may block this by default and/or you'll probably need to pay extra for this.

After SIM activation, you can send text messages (Mi Messages) to other Mi users using internet connection (like i-messages).

You will be able to synchronize your messages into Mi Cloud and this also enables the Mi Find Device feature which allows you to track your phone’s location from your online Mi account.

Note: To enable/disable Mi Messages go to Settings -> System Apps -> Messaging and reboot

Commands

adb shell pm uninstall --user 0 com.xiaomi.simactivate.service

To put it back:

adb shell cmd package install-existing com.xiaomi.simactivate.service

Every removal listed here is per-user only: the system image is untouched, and the restore command puts the app back from the copy already on the device. Nothing is downloaded.

This is not the directory. Here we say what a package is in general; what happens on your particular television is on your model's entry, and that one wins. The same package can be dead weight on one set and hold the home screen up on another.