Hello
to put script in /etc/init.d/SXXNamescript
but in recalbox.conf look theses lines : https://github.com/recalbox/recalbox-os/wiki/recalbox.conf-(EN)
;system.power.switch=PIN56ONOFF # https://github.com/recalbox/recalbox-os/wiki/Add-a-start-stop-button-to-your-recalbox-(EN)
;system.power.switch=PIN56PUSH # https://github.com/recalbox/recalbox-os/wiki/Add-a-start-stop-button-to-your-recalbox-(EN)
;system.power.switch=PIN356ONOFFRESET # https://github.com/recalbox/recalbox-os/wiki/Add-a-start-stop-button-to-your-recalbox-(EN)