Sinden light gun to work on the latest 7.2.2 version where it's supposed to be supported "out of the box"
The light gun system works "out of the box".
Sorry, but I don't know this "Sinden light gun", and I haven't seen anywhere that it is compatible, the documentation says that LightGun is compatible with Wiimote With Mayflash USB Converter:
https://recalbox.gitbook.io/documentation/hardware-compatibility/compatible-devices/controller#lightgun
Read the complete Lightgun system documentation:
https://recalbox.gitbook.io/documentation/v/francais/usage-basique/fonctionnalites/lightgun-de-recalbox