That procedure is what is on the DS dac update. But the instruction on the document with the update :
Place the thumb drive in the USB slot on the back of the unit marked FW.
Using the front panel Logo LED button, place the unit in standby.
Using the switch in the back of the unit, power off the unit and then power it back on.
so i assume the unit should be on standby when i put the USB in.
I’ve always completely turned it off first, but it ultimately shouldn’t matter. I’ve had no trouble doing it the way I do it with all of our components.