Pardon if I rehash somehting or dont have the nameology of the part right, I'm not a KTM expert, I just fiddle with a lot of engines... :)
Being able to plug into the ECU would tell you something as well. (Kick stand switch bad? you should be able to see the status...)
Does the cluster do the correct little self test dance when you power up the bike?
Check all your fuses with a meter,,, I've had them blow and not collapse so they look ok...
When I hear the symptom you originally had I start with the battery and follow the power with a volt meter to the ECU.
(Electrical harness issues,,, always fun...)
Crank position sensor is the most common reason Electronic ignition stops. And almost NO ECU's can test it...