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CP370 compatibility with older Raymarine MFD – How to downgrade

|14/01, 2025

CP370 compatibility with older Raymarine MFD – How to downgrade

Step-by-step guide to downgrade CP370 and restore compatibility with E-Classic, C-Wide, E-Wide, and G-Series.

With the release of CP370 software (v20.0 application / v18.00 platform) or later versions, older multifunction displays (MFD) such as E-Classic, C-Wide, E-Wide, and G-Series are no longer compatible. If you connect a new CP370 with the latest software, it will not communicate with these older MFD models.

Summary – How to make CP370 compatible with older MFDs

To use CP370 with an older MFD like E-Classic, C-Wide, E-Wide, or G-Series, you must downgrade the CP370 to v13.34 application / v15.02 platform. Since the CP370 cannot communicate with older MFDs during the downgrade, you will need an AXIOM MFD with LightHouse v3.14.88 or higher to perform the process.

Important note: Countries covered by PSTI regulations (e.g., UK) do not allow downgrading to software versions lower than v21.03.35.

Step-by-step guide for CP370 downgrade

  1. Download the Downgrade .ISO file for CP370 from this link.
  2. Unpack the file and copy the .ISO file to a MicroSD card formatted to FAT32 (file size under 50 MB).
  3. Connect the CP370 (with v20.0 or higher) to a transducer.
  4. Connect the CP370 via RayNet to an AXIOM MFD with LightHouse v3.14.88 or higher.
  5. Start both AXIOM and CP370 simultaneously.
  6. Open a full-screen SONAR app on the AXIOM and open the sidebar menu.
  7. Select the transducer before entering the SONAR menus.
  8. Go to Settings (three gears) and select the Sounder tab.
  9. Click on Reset sounder and confirm.
  10. Insert the MicroSD card into the AXIOM's card reader (Slot 1).
  11. From the home screen, select Settings → Update software.
  12. Click on Check SD card.
  13. Select CP370 from the list and confirm downgrade to v13.34.
  14. Start the downgrade process.
  15. Once the downgrade is complete, turn off the CP370 and AXIOM and disconnect the CP370.
  16. Connect the CP370 to the older MFD system via SeaTalkHS and check functionality.
  17. Set depth offsets and select the correct transducer type.

Tips for best results:

  • Ensure the AXIOM is running the correct software version before downgrading.
  • Use a correctly formatted MicroSD card (FAT32).
  • Follow the steps carefully to avoid compatibility issues.