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The WNRO Firmware Update for the Güralp CD24


Some GPS receivers report incorrect dates because of the GPS Week-Number Roll-Over problem (WNRO). The latest generation of receivers - those with serial numbers beginning G3… - do not have this problem but, when replacing receivers, it is necessary to update the firmware of Güralp CD24 digitisers so that they can operate correctly using these receivers. This page describes that upgrade.

Updates are not necessary (or even possible) for all Güralp digitisers. Please check the following points carefully

  • Peli-cased DM24
  • Cylindrical DM24
  • Cylindrical DM24SxEAM
DM24 in a peli-case   DM24 in a metal cylindrical case This upgrade does not apply to DM24 digitisers in any form. DM24 Mk3 users should refer to the DM24 Mk3 WNRO firmware upgrade page.

  • Affinity
Affinity This upgrade does not apply to Affinity digitisers.

  • Minimus
  • Minimus+
  • Minimus₂
Minimus   Minimus+   Minimus₂ and Minimus Lite This upgrade does not apply to Minimus digitisers in any form. The GPS/GNSS receivers shipped with Minimus and Fortimus systems are already WNRO-compliant.

  • CD24 stand-alone
  • 6TD
  • ESPCD with CD24
  • 5TD Compact with CD24
CD24   6TD   3ESPCD with break-out box This upgrade only applies to compatible CD24 digitisers, whether stand-alone or embedded in instruments such as the 6TD, the 5TCDE and some 3ESPCDs.

Compatible digitisers and instruments can be identified by the firmware revision which they are currently running: this must be either 2xx or 3xx.

To find out what version of the system program your digitiser is currently using, right-click on the digitiser’s icon (, not the Local or the Comxx icons) in Scream!’s main window and select Configure from the pop-up menu. This will open the Configuration setup window. The version number is given in the Firmware revision box, as shown below:

Alternatively, open the Configuration → Data handling → Data Acquisition page in the EAM's web interface. The version number is given in the software version box, as shown below:

If your CD24 is currently running a firmware version 1xx, please contact for advice.
If your CD24 is currently running a firmware version between 200 and 279 and has built-in Ethernet or WiFi, please see the special notes at Upgrading units with Ethernet from before version 279

Upgrade instructions

There are two ways to upgrade a CD24: automatic and manual. Use the automatic method if …

If this is the case, follow the instructions under "Automatic Upgrades", below.

If you do not have access to an EAM and wish to upgrade a stand-alone CD24 or a CD24 embedded in a 6TD or 3ESPCD instrument, please skip to "Upgrading without an EAM".

Whichever method you choose, please be sure to read "After upgrading..." once the upgrade is complete.

Automatic Upgrades

If you have an EAM or an instrument which contains an EAM, the EAM should be used to automate firmware upgrades of attached or integrated digitisers. This is the safest and fastest way to upgrade a CD24.

The latest version of Platinum software always includes the latest CD24 firmware so, first, ensure that your EAM's firmware is up-to-date by selecting Firmware from the Tools menu in the web interface and then clicking the Upgrade button - see the release notes for Platinum firmware for more details. Connect your CD24 to the EAM if necessary and, from the web interface, visit the configuration page for the digitiser. If an upgrade is available, this page will notify you and a check-box near the bottom will allow you to upgrade the firmware on the CD24 when the page is submitted:

If you prefer to use the EAM's command line, the necessary commands can be as simple as

upgrade dm24-upgrade PortA

The first command upgrades Platinum from the Internet and the second upgrades the attached digitiser firmware using the image embedded within Platinum. Please see section 8.2.3 of the Platinum manual for details of the dm24-upgrade command-line tool. (Note that, although this command is called dm24-upgrade, it can be used to upgrade CD24s as well.

Now read "After upgrading...".

Upgrading without an EAM

You can update the digitiser firmware using any terminal program which supports the X-modem protocol, such as minicom (for Linux users), ExtraPuTTYExtraPuTTY is an extension to Simon Tatham's free (both as in “free speech” and also as in “free beer”) and highly-recommended PuTTY software, an SSH client, telnet client and serial terminal emulator that runs under Windows and Linux. In addition to all the features of PuTTY, ExtraPuTTY provides x-modem, y-modem and z-modem file transfers over serial links. ExtraPuTTY can be downloaded from SourceForge's ExtraPuTTY page. or Scream!. Use of Scream! is recommended. If you wish to proceed with an alternative emulator, you will need to adapt the instructions below accordingly.

To install this firmware using Scream!:

  1. Download

    The latest CD24 firmware

    an 89 K .zip file containing:

    • system program v.328

  2. Unzip the downloaded file into a folder on your PC. We recommended that you make a new folder for this purpose so that the required file can be found easily when required, later in this procedure.

  3. Right-click on the digitiser’s icon () in the main window and select Terminal from the pop-up menu:

    A terminal window should open. Check that there is two-way communication with the digitiser by pressing enter. The digitiser should reply with ok on a new line.

  4. Type ok-1 to enable advanced commands. The instrument will reply with a message describing the current firmware version.

  5. If the current version is v.328, the upgrade has already been performed. Otherwise, type load and key enter The digitiser will display load C and wait for 10 seconds for you to provide a firmware file.

  6. Right-click on the terminal window and select Send file…:


    Navigate through the directories on your computer to find the directory containing the firmware file. It will, at first, be invisible so click on the Objects of type: drop-down menu and select All Files:

    Now you can see the firmware image file:

    Select dm32_1a_328.hex and click the 'Open' button

  7. If the file opens successfully, Scream! will show the progress of the upload:

    Depending on the speed of the link, it may take up to 20 minutes to transfer the firmware. If you are using Scream, the progress indicator will display a reasonable estimate of the time remaining.

  8. Towards the end of the transfer, the system will pause for a few seconds and then print a blank line. The final eight addresses are then printed followed by the "ok" prompt, after which Scream will close the session:

    Click to continue and close the terminal window.

    If you are using a terminal emulator other than Scream, you will need to close the emulator window yourself.
  9. At this point you may want to switch the instrument or digitiser off and then back on, to ensure that it restarts properly.

  10. Allow 30 seconds for the digitiser to restart, then open another terminal window. Type ok-1. The digitiser will reply with a message containing the firmware version number.

    If this now shows v.328, as above, you have successfully updated the firmware. Close the terminal window to resume data transmission.

    If the unit has not upgraded, please see the special notes at Units that will not upgrade.

This completes the upgrade procedure.

After upgrading...

Upgrades from some early firmware versions can interfere with the setting of the high-pass filter. To check, right-click on the digitiser's icon (not the Local or the Comxx icons) in Scream!’s main window and select Configure from the context menu. This will open Scream's Configure dialogue: Select the Output Control tab. There should be a drop-down menu to configure the high-pass filter but, in some cases, the menu will be missing, as shown here:

Scream's 'Configure', 'Output Control' pane with missing high-pass filter menu

If this is the case, open a terminal to the digitiser by right-clicking on its icon in the source tree and selecting Terminal from the context menu. In the resulting window, type the commands


The terminal window will close. If you now revisit the Output Control tab of the Configure dialogue, the menu should be restored, as shown below:

Scream's 'Configure', 'Output Control' pane with the high-pass filter menu showing

You can now configure the filter to your desired setting.

Special cases

Units that will not upgrade

Some units have an incompatible boot-loader that will not accept the new firmware. Attempting to flash the latest file will not damage your unit. However: the upgrade will not succeed and the firmware will revert to an earlier version.

Should this affect your unit, please email for further instructions and a compatible firmware release.

Upgrading units with Ethernet from before version 279

The Ethernet enable flag has moved in CMOS so when upgrading the firmware, Ethernet is inadvertently switched off. This is an issue if upgrading firmware on remote units over a network connection. To upgrade units from v.278 and earlier, this work around must be used. Open a terminal and enter:


Now load the new code as normal. When complete, connect to the sensor again and open a terminal to enter:


For more information, first contact your local distributor or email .