Suddenly your Garmin 1000 screens go dark as though you had blown an Avionics buss breaker. If at the same time you are using the Honeycomb Alpha yoke, check the position of the magneto switch. If it is in the Start position, turn it back to both. This should restore your Garmin screens.
More generally, always remember to turn the switch back to Both after engine start.
Keeping the starter on drains your battery, which is why your screens eventually turn black.
I believe I read somewhere that the next version of the Alpha will feature a spring loaded starter switch that returns to Both by itself much like the real one in the C172 and others.