Hello,
Yesterday i was trying to calibrate Racestart BLHeli REV35 35A ESC , Suddenly main LED of Pixhawk 2.4.8 is stopped blinking.
From that movement - i cant connect Pixhawk to Mission planner, other lights are blinking except main LED, Buzzer also making strange noise.
My Pixhawk got detected for a few seconds before disappearing again from device manager. I managed to upload the firmware again after some trial and error.
Is your pixhawk really not detected at all?