How do you set factory default on Sony HCD-H801?

To set the Sony HCD-H801 to factory default, first, turn off the unit. Then, press and hold the "Power" button while simultaneously pressing the "Reset" button (usually located on the back or bottom of the unit). Release both buttons after a few seconds; the system should reset to its factory settings. Make sure to back up any important settings or data before performing this action, as it will erase all custom configurations.