External 4.0TB hard drive not detected on reboot

When I reboot my Lenovo T430, one of two external 4.0TB HDDs restarts OK most of the time;
if it isn't immediately detected, I can easily power off/power on with its on/off switch.
The 2nd 4.0TB HDD is never detected on a reboot, and I have to unplug its USB connection
and plug it back in to activate automount. Is there a way to control its power or USB
connection with software to avoid having to install a power switch or risk wearing out its
physical USB port ?
I'm using trisquel_10.0.1 (nabia).