Trelock FC 520 - Miles vs. Kilometers

Maybe it will help somebody. I was trying to reset the Trelock FC 520. "bike computer" to KM after a battery change. It switched from KM to miles. I had no idea how to change it back. If you open the settings you only get a menu with 3 items. Turned out, you need to press the "SET" and the "MODE" button in the same time. I didn't find this in the manual

Aerial photos - DIY