If there are no ports shown in the Host Serial Port for
upload drop-down list, ensure that you have connected the
Pixhawk® Series flight controller properly to the
host computer. Even after connecting the flight controller properly, if the
serial port does not appear and it is not detected in the Windows Device
Manager, ensure that the Pixhawk Series flight controller is flashed with PX4
firmware. If you were using ArduPilot firmware before, or if you are not sure
about the current firmware type and version of the flight controller (for
example, if it is a new Pixhawk flight controller board), flash the latest
stable release of the PX4 firmware, using QGroundControl. Refer to QGroundControl documentation for more details on uploading the PX4
firmware.
When you perform the Test Connection step of the Hardware
Setup process to upload the PX4 firmware to a Pixhawk® series flight controller, the Hardware Setup screen may not
respond even after a long time (the busy spinner remains displayed on the
screen).

The reasons for this issue and the corresponding troubleshooting actions are described in the below table:
| Reason for the Issue | Action Required |
|---|---|
The serial port that you selected in the | Close the Hardware Setup screen, and restart the
Hardware Setup process again (including the |
On the dialog box that appears instructing you to reconnect the flight controller, you did not click OK within 5 seconds after reconnecting the flight controller (as instructed in the dialog box). You can verify if this is the reason for the issue, if the following line appears at the MATLAB command prompt:
| Disconnect and reconnect the Pixhawk Series flight controller to the host computer. Whenever the dialog box appears instructing you to reconnect the flight controller to the serial port, ensure that you click OK on the dialog box within 5 seconds after reconnecting the flight controller. Tip The 5-seconds limit applies only to the time after reconnection. Therefore, you can first disconnect the USB port from the host computer without worrying about the time limit; but, ensure that you click OK within 5 seconds after reconnecting the cable to the USB port of the host computer. |