Bad Firmware Upgrade Bricks WD Sharspace

So I foolishly tried to upgrade the firmware on my two year-old 4TB sharepace, only to end up with a dead unit - power it on, it just sits there with all the lights on, but in particular the little blue check mark light.  It’s completely unresponsive to all three buttons - power, reset, and the strange button that I never bothered to learn the function of.

So I buy another one.  I figure the software is f’d on the old one and maybe I can rebuild it a drive at a time, swapping its drives with those in the new one, starting with drive four and working my way down.  Four mind-numbing days later I’m on the last drive but wait - it shows signs of the personality (system name, user accounts) of the old device.  Kind of makes me wish I’d swapped all the drives at the beginning…

Anyway, I finish the rebuild, all four drives, do a reboot to convince me that it’s working.  Then I pull all the drives and stick them back in the original unit.  Guess what - it’s still bricked.

Put the new drives back into the new unit and I have to rebuild the raid set (I kind of expected that).  That’s where my story is right now.

When the raid set is rebuilt, I guess I’ll swap drives again to see if the old drives will still boot in the new unit.  I’ll put the new drives in the old unit to see if it is still bricked.

So am I right in assuming  there’s some sort of firmware on the enclosure itself that is trashed, and if so, how can it be fixed?  It looks to me that the brains are on a single card, held in by a bunch of screws to stand the pressure of users swapping in and out drives (the drive sockets look to be soldered right to the card).  Looks like I could replace it if only I had something to replace it with.

Dude, why not trying to replace the whole thing with WD? o.o