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  3. How to Disable VNC in cPad Firmware
Updated: 31 July 2026

How to Disable VNC in cPad Firmware

This article provides step-by-step instructions for disabling VNC on Cpad devices. The process differs depending on whether you are modifying a single device via SSH or applying the change to the firmware for multiple devices. Follow the appropriate method below based on your deployment needs.

Background

VNC is disabled by default on Cpad devices running the Cpad Papercut App firmware version 2.2.1 and newer (released November 2019). However, this is not the case for the Cpad VL firmware, where VNC may remain enabled by default. Disabling VNC is recommended to enhance device security.

Prerequisites

  • Administrator access to Cpad devices (via SSH or firmware files)

  • SSH client (for device-level changes)

  • 7-Zip or compatible archive tool (for firmware-level changes)

  • Text editor for modifying shell scripts

  • Backup of the cpad-server.sh file or firmware before making changes

Disabling VNC on a Single Cpad Device via SSH

  1. Connect to the Cpad via SSH

    • Use your SSH client to connect to the Cpad device using its IP address and administrator credentials.

  2. Navigate to the Cartadis directory

    • Run the following command to switch to the appropriate directory:

    • cd /usr/local/Cartadis

  3. Edit the cpad-server.sh file

    • Open the file with your preferred text editor (e.g., nano cpad-server.sh).

    • Locate line 22 in the file. This line starts the VNC server.

    • Add a # at the beginning of the line to comment it out and disable VNC.

    • Save and close the file.

  1. Restart the relevant services or the device

  • To apply the changes, restart the affected service or reboot the device.

Disabling VNC for Multiple Devices by Modifying Firmware

If you need to apply this change to multiple Cpad devices, you can modify the firmware update file to include the VNC disablement before deploying it.

  1. Obtain the firmware update file

    • Identify the firmware update file you plan to deploy (e.g., pcvlapp-v3.X.X.cpadv2).

  2. Extract the firmware contents

    • Use 7-Zip or a similar tool to open the firmware file as a folder.

    • Navigate through the archive to locate the following path:

    • pcvlapp-v3.X.X\cpad\cpadroot.tgz\cpadroot.tar\usr\local\Cartadis\

  3. Edit the cpad-server.sh script

    • Open cpad-server.sh in a text editor.

    • Find line 22 (the line that starts the VNC server) and comment it out with a # at the beginning of the line.

    • Save the modified file.

  4. Repackage the firmware

    • Ensure the modified cpad-server.sh is saved within the firmware structure.

    • Compress the files back into the original firmware format, maintaining the correct folder structure and file permissions.

  5. Deploy the updated firmware

    • Follow standard procedures to update the Cpad devices with the modified firmware.

Best Practices and Notes

  • Always back up original files or firmware before making any modifications.

  • Test changes on a single device before deploying widely.

  • Commenting out the VNC start line is reversible; remove the # to re-enable VNC if required later.

  • This procedure was originally documented by Grégory Ninet (Cartadis, March 2022).

Troubleshooting

  • If VNC is still accessible after these changes, verify that the cpad-server.sh file was saved correctly and that the device was restarted.

  • Check for typo errors when commenting out the line; it should begin with a single # character.

  • Ensure there are no other startup scripts enabling VNC elsewhere.

Support

For further assistance, contact the internal IT support team or reach out to Cartadis support if firmware issues persist.