[achapman]

I have a 12000. Basically it is similar to a 4100 and all the troubleshooting procedures for a 4100 can be used. The one thing to note is that it won't run on the latest (i.e. last) versions of SnapOS unlike the 4100. Like the 4100 it is limited to 128Gb hard disks.

I would remove all your present disks and use a single new disk until you get it going again. Once it is up and running you can refit the original disks as they were.
It has been a while since I recovered a 4100 or 12000 so I can't remember the procedure, but I think it means doing a factory reset and possibly reflashing the unit.

Andrew