Powering on/off usb ports?

Hi all,
just purchased a Vontar X3 (s905x3) with 4/64 GB and installed CE 9.2.7 on a micro SD card. I noticed that powering the box off leaves the usb2.0 port on and keeps the attached fan running. I have been searching the forum but failed to find any solution. And I was unable to toggle the USB power switch on the Hardware page of Coreelec settings since it is absent from that page. This is from a screenshot I stumbled on during my search. Does anybody have a solution to shut the port off or shall I just live with that and unplug the fan each time I turn the box off. Not the most user friendly …
TIA