Switch off OVI40UI
Press and hold push buttons F1 F3 F5
Switch on OVI40, wait for text message, release F1 F3 F5
Press simultaneously Band+ and Band- buttons to confirm resetting of settings
When UHSDR has bootet up long-press System Menu (F1 button) to save values
Hint:
If you just want to play around with default setting without loosing your own configuration: