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Frequently Asked Questions

System Issues​

System Fails to Boot​

We provide standard system images and Phoenix system images.

  • Standard System Image: Includes a partition table and can be directly installed onto the system boot medium.

If using a standard system image, refer to the Quick Start → Install System tutorial for installation.

  • Phoenix System Image: Does not include a partition table and requires the Phoenix tool to flash the system image.

If using a Phoenix system image, refer to the tutorials Install System to MicroSD Card and Low-Level Development → Install System in FEL Mode based on your system boot medium.

First, confirm whether the installed system image is correct. If the system image is correct, you can use serial debugging to obtain system boot logs and troubleshoot based on the log information.

Remote Access Issues​

Unable to SSH​

The factory system image enables the SSH service by default. Generally, you only need to ensure that the Cubie A7A and the PC are on the same local network to access it via SSH.

Troubleshooting Steps:

  1. Check whether the Cubie A7A is connected to the network and whether the IP address is correct: Use the ip a command to view detailed network connection information.
  2. Check whether the Cubie A7A and the PC are on the same local network: Use the ping command to test if their IP addresses can communicate.
  3. Check whether the SSH service is running: Use the sudo systemctl status ssh command to check the SSH service status.

Unable to Use VNC​

VNC remote access requires manual configuration of the VNC server. If configured according to the tutorial, the VNC server will automatically shut down after each reboot or shutdown.

Troubleshooting Steps:

  1. Complete the VNC remote configuration as per the tutorial.
  2. Ensure that SSH remote access is functioning correctly.
  3. Check whether the VNC server is running: Use the vncserver -list command to check the VNC server status.
  4. Use ip:5901 for VNC remote access, where ip is the IP address of the Cubie A7A.

Serial Port Issues​

Failed to Open Serial Port​

If you encounter the error Error: Permission denied, cannot open /dev/ttyUSB0 when opening the serial port:

Follow these steps to troubleshoot:

  1. Check whether the serial device is properly connected.

  2. Check the serial device permissions.

For example, on a Linux system, if the serial device lacks sufficient permissions, run the following command in the terminal to grant all users access to the serial device:

Linux@host$
sudo chmod 777 /dev/ttyUSB0
  1. Check whether the serial device is occupied by another program.

Network Bandwidth Testing​

Port Occupied​

If the system displays the error iperf3: error - unable to start listener for connections: Address already in use, it means the iperf3 process is occupying port 5201.

Solution:

  1. Check the iperf3 process:
Linux@host$
ps -ef | grep iperf3
  1. Terminate the iperf3 process: Replace <PID> with the PID of the iperf3 process.
Linux@host$
sudo kill <PID>