I’d suggest you send a note to support… if the following doesn’t work. Kind of going back to what you’ve already done…
I have not seen it like you describe but I’ve heard of the unrecognized board signature… Generally unloading and reloading isn’t the answer… it just means there’s a bug somewhere… in the drivers or the install/remove software.
This thread had success, but it appears he missed a step in the installation somehow… it’s a Windows machine, so no telling… no mention of the busy/disconnected message.
Good luck…