Hello,
MAC address could be only found after robot connects to wifi on app.
The robot cleaner could also connect to wifi sent by a hotspot like a phone.
Therefore, you could get 2 smart phones( A and B) to connect robot cleaner to Internet.
1. Enable phone A's hotspot function in phone's setting and set up wifi name and password(the wifi must have a password) like a router.
2. Use phone B to install app Mi Home and follow instructions on app to make robot cleaner connect wifi sent from phone A.
3.Finally, you could use phone B to access robot cleaner on app and know robot's MAC address like attached picture.
thanks
jackyjoy