Allegedly, on or about 7 December 2017, Fulko Hew sent:
> To disable the Advanced Power Management and to stop the head
> unload/clicking I've always used:
>
> hdparm -B 255 /dev/sda
>
> But on this machine/drive, it doesn't seem to work;
> or at least it only works for a short while, and then it starts
> unloading again.

Is there a laptop mode set somewhere?  That'd be a conflicting
configuration.

https://wiki.archlinux.org/index.php/Laptop_Mode_Tools