@yeeshkul hi
Go in your recalbox.conf file, open it using notepad++, check the required line :
# System Variable
# You can configure your recalbox from here
# To set a variable, remove the first ; on the line
# ------------ A - System Options ----------- #
# Uncomment the system.power.switch you use
;system.power.switch=ATX_RASPI_R2_6 # http://lowpowerlab.com/atxraspi/#installation
;system.power.switch=MAUSBERRY # http://mausberry-circuits.myshopify.com/pages/setup
;system.power.switch=REMOTEPIBOARD_2003 # http://www.msldigital.com/pages/support-for-remotepi-board-2013
;system.power.switch=REMOTEPIBOARD_2005 # http://www.msldigital.com/pages/support-for-remotepi-board-plus-2015
;system.power.switch=WITTYPI # http://www.uugear.com/witty-pi-realtime-clock-power-management-for-raspberry-pi
;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)
;system.power.switch=PIN356PUSHRESET # https://github.com/recalbox/recalbox-os/wiki/Add-a-start-stop-button-to-your-recalbox-(EN)
line 14 : simply remove the ";" in front on the pin356ONOFFRESET
Save your file, and that's all.
Don't forget recalbox is an operating system !