Emergency reset loads the defaults for the last mapped button when 4 keys are held for 3 seconds.
After 3 seconds more all buttons are set to default.
This prevents that the Player becomes unusable.
Protection will prevent unmapping the last button for essential buttons.
Essential are: Directions, Confirm, Cancel and Settings menu
However this can still make the Player unusable, therefore the emergency reset.
When loading the configuration unmapped protected buttons get the default assigned.