With Debian 9.4, brltty, and the tsi driver for PowerBraille 80, I edited the key bindings file to use concave + convex to toggle between 6- and 8-dot Braille, and that works better for Andre than the default 3-button binding (3 buttons are awkward). Is there a way to set the default to 6-dot braille at boot? Thanks for all your support!