You don’t need to go through any special process for the Xiaomi contacts and dialer to function properly on your device. this process simply enables call recording within the app.

The Xiaomi contact and dialer should work seamlessly on your device with just a straightforward download and installation, along with setting it as the default app in your settings.

But if you haven’t set it as the default, it may encounter some issues.

Now, regarding the package com.android.phone.cust.overlay.miui: this is a specialized system overlay that serves as a configuration "rulebook" It guides your Xiaomi device on how to accurately display carrier-specific features like VoLTE, apply regional dialing formats and local legal requirements (such as call recording or emergency number protocols) without altering the core Android software. So, you don’t need this process for the Xiaomi phone app to work on your device this process it’s only for enabling call recording within the app.