Hi. I'm having what I think must be a similar problem.
Here's my error message:
In file included from C:\Users\johnn\OneDrive\Desktop\sketch_may4b\BlinkSerial\BlinkSerial.ino:1:0:
C:\Users\johnn\AppData\Local\Arduino15\libraries\Firmata/Boards.h:1123:2: error: #error "Please edit Boards.h with a hardware abstraction for this board"
#error "Please edit Boards.h with a hardware abstraction for this board"
^~~~~
exit status 1
Compilation error: exit status 1
and I've tried to add various versions of what's here to the boards.h and nothing is working.
help would be hugely appreciated.