Is anybody home? I updated yesterday, July 9, 2024 to the newest version of XP12.   Now, when I turn on the Batt switch, and start the APU and put it on its bus, no avionics come on.  All the screens stay black.  Well, that's a flight cancellation.  I really have zero idea how to troubleshoot this issue, so of course I wonder if the new update caused a conflict with the Challenger systems?  I would think this is a known issue since the airplane is now unflyable.  But it's always possible th