I've just merged support for the SV-806 80 column card. As with the TK-02 on the Einstein this is available in the generic console by selecting mode 10.
There's still a couple of issues unfortunately:
- I've not yet managed to disable the cursor
- The ROM based fgetc_cons() doesn't work so you'll have to switch to the inkey version with -pragma-redirect:fgetc_cons=fgetc_cons_inkey
There's a fully filled square at (I think) character 192 (print in raw mode) so graphics similar to the Einstein TK-02 can be done.