I am trying to determine if my 3DR PX4 FMUv2 (https://docs.px4.io/en/flight_controller/pixhawk.html) is dead or not. I've been using this device for about three years and have uploaded firmware to the board routinely during this time with no issues. Today it seems after a firmware upload the board no longer was visible on the list of devices (Windows 10). When plugging the board in via micro USB my Windows device manager shows a "PX4 FMU (COM4)" under the serial port men but then it suddenly disappears from the list of COM devices. As such, QGC or mission planner or the CMAKE build system is unable to find the board so I have no way of uploading new firmware.
Since COM4 was not accessible i wanted to see if i could access the serial shell over another serial line ( ttyS6 on the Pixhawk). This is something i've routinely done in the past so there is no issue with the wiring here. I modified my rc.txt on an SD card and specified the nuttx shell to point to ttyS6 like so:
nshterm /dev/ttyS6 &
I also added in a tone alarm as well. Plugging in the device again I was able to see the serial device that was connected to ttyS6 was available but attempting to access the shell over putty revealed nothing (ie: no feedback when i typed - just a blank screen). I also did not hear any tone from the device.
In the past few weeks I did notice that when i ran the python script to upload the firmware the progress would sometimes halt and would need to re-flash again. The "erasing firmware" part works fine but then the "flashing firmware" would sometimes get stuck randomly and say something like "missing byte" or something along those lines. This has never happened up until recently.
Regarding what LEDs are on in this current state, this is what I see:
PWR: Solid Green
B/E : Solid Orange
PWR: Solid green
B/E: Solid Orange
ACT: Flashing blue
I'm not sure what state it's in right now - if anyone can shed some light on this I would greatly appreciate it.