Gen 2 Firewire to Thunderbolt

I have a late 2013 iMac running Sierra and a gen 2 Drobo w/ firewire 800 & USB.

I am trying to use 1 of 2 configurations:

1: I have an Apple FW800-Thunderbolt adaptor. When I use this, the Drobo doesn’t always show up after a reboot. Plus, the finder will sometimes hang.

2: Connect to a USB port. The iMac has USB 3 which should be backward compatible to USB 2 which is what the Drobo uses. This seems slightly more stable, but the drive takes upwards of 10-minutes to mount after a reboot… When it mounts. There are still times when I have to unplug the Drobo (the power, not the USB) in order for it to mount. Also Finder still hangs, though not as frequently as w/ the Thunderbolt option above.

I’ve seen where the dashboard sees the drive, but Disk Utility doesn’t.

Meanwhile, on my slowly dying 2007 Mac Mini, I connect with a FW800-FW400 cable and it’s rock solid.

hi, is there a way for you to check (and compare) the usb and firewire drivers, just in case the mac mini is using newer drivers (or if the sierra has some newer drivers available for it?)

for me on windows, ive always used usb with my drobos, and i believe usually usb is preferable for certain things (like updating firmware via mac) but can i check if you can try with some different usb ports (and possibly with another usb cable, even a basic usb2 cable?)