I had one batch of drives that needed a firmware update.  The drives were all in USB cases, but to apply the firmware updates using the vendor's utility I had to remove each drive from the USB case and install in an old PC.


Yes, that sounds familiar :-)

I did manage to update a couple of Seagates here through USB with hdparm, but it took a bit of trickery to figure out the right options and to extract the actual firmware binary file from the manufacturer downloadables.