When the Pixhawk is connected to QGC using USB, I can see the entire setup menu:
Firmware - this says to unplug the PH from USB
All my sensors are calibrated (green). QGC shows the position and attitude of the Pixhawk. Everything looks good at this point.
When I disconnect the USB cable I loose connection, and the setup menu now shows only Summary and Firmware tabs. There is nothing in the Summary except the statement "vehicle settings and info will display after connecting your vehicle. Click Firmware on the left to upgrade your vehicle."
When I click Firmware I get the message
"QGroundControl can upgrade the firmware on Pixhawk devices, SiK Radios and PX4 Flow Smart Cameras.
All QGroundControl connections to vehicles must be disconnected prior to firmware upgrade.
Please unplug your Pixhawk and/or Radio from USB."
At this point I already have the Pixhawk unplugged!!! It does not prompt me to plug it in to do the firmware update. When I plug it in I'm now back where I started from. I never see the menu for selecting a device to update.
I hope this makes it clearer.
Thanks for responding so quickly.