The Home Key is not working, Recent/Back Key is not working too, the Notification Bar cannot be swiped down. I experienced this problem on my Xiaomi Mi A1 phone after I messed-up something switching from A and B boot partitions. Also the Google Play Store did not worked properly, preventing from installing new applications.

Fortunately I found a procedure that fixed the problem, without a factory reset.

The trick is to run the SetupWizardUpgradeActivity from the com.google.android.setupwizard app. The app may have different names upon localization, e.g. Setup Wizard for English or Configurazione Android for an Italian version.

A common is to install the Nova Launcher app, which has a widget capable of starting an app activity.

• Install the Nova Launcher app.
• Long tap over a free dekstop space, to add a new widget.
• Search the Nova Launcher Activity Widget, and place it on the desktop.
• Search the Setup Wizard in the proposed list, from the sublist choose the SetupWizardUpgradeActivity.
• Start the activity from the widget just added and complete the procedure.
• Now you can uninstall the Nova Launcher app.

• https://in.c.mi.com/thread-699192-1-0.html
• https://in.c.mi.com/thread-699854-2-0.html
• https://www.youtube.com/watch?v=UhNNhOD0wp8