I have asked same question Normis et MUM Belgrade 3 (or 4 ? )years ago.
He told me that USB power disable should be minor intervention and that he will transfer my request.
Until then, nothing.
how ? I have only serial port to chooseyes, if ups is connected via USB, that USB port can be used to set up UPS at /system upsdid you tryed to connect it to routeros?if your ups is connected via usb what shows system usb print?