How to Use the GR-8018 “Save-on-Shutdown” Feature to Preserve Configuration, IMU Calibration, and Satellite Orbit Knowledge?

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#1 · June 5, 2026, 9:04 am

Quote from GPSWebShop Official on June 5, 2026, 9:04 am
The GR-8018 is designed with the u-blox NEO-M9V chipset. Users can use the “Save-on-Shutdown” feature described in Section 3.9, “Save-on-shutdown feature,” of the NEO-M9V Integration Manual UBX-21029776:

https://content.u-blox.com/sites/default/files/NEO-M9V_IntegrationManual_UBX-21029776.pdf

To configure this feature, users need to use the u-blox configuration tool u-center, which can be downloaded from the u-blox website.

For your convenience, I have included Section 3.9 Save-on-shutdown feature below.

====================================

3.9 Save-on-shutdown feature

The save-on-shutdown feature (SOS) enables the u-blox receiver to store the contents of the battery-backed RAM to an external flash memory and restore it upon startup. This allows the u-blox receiver to preserve some of the features available only with a battery backup supply present (preserving configuration, IMU calibration, and satellite orbit knowledge) without having a battery backup supply present. It does not, however, preserve any kind of time knowledge. Save-on-shutdown must be commanded by the host. The restoring of data on startup is automatically done if the corresponding data is present in the flash. Data expiration is not checked.

The following outlines the suggested shutdown procedure when using the save-on-shutdown feature:

With the UBX-CFG-RST message, the host commands the u-blox receiver to stop, specifying reset mode 0x08 ("Controlled GNSS stop") and a BBR mask of 0 ("Hotstart").

The host commands the saving of the contents of BBR to the flash memory using the UBX-UPD-SOS-BACKUP message.

For a valid request the u-blox receiver reports on the success of the backup operation with a UBX-UPD-SOS-ACK message.

The host powers off the u-blox receiver.

The startup procedure is as follows:

The host powers on the u-blox receiver.

The u-blox receiver detects the previously stored data in the flash. It restores the corresponding memory and reports the success of the operation with a UBX-UPD-SOS-RESTORED message on the port on which it had received the save command message (if the output protocol filter on that port allows it). It does not report anything if no stored data has been detected.

Additionally the u-blox receiver outputs a UBX-INF-NOTICE and/or a NMEA-TXT message with the contents RESTORED in the boot screen (depends on the configuration of the port and information messages) upon success.

Optionally the host can deliver coarse time assistance using UBX-MGA-INI-TIME_UTC for better startup performance.

Once the u-blox receiver has started up it is recommended to delete the stored data using a UBX-UPD-SOS-CLEAR message. The u-blox receiver responds with a UBX-ACK-ACK / UBX-ACK-NAK message.

CAUTION
Note that the save-on-shutdown feature works correctly only when the receiver has a valid time information when saving the SOS-BACKUP.

The GR-8018 is designed with the u-blox NEO-M9V chipset. Users can use the “Save-on-Shutdown” feature described in Section 3.9, “Save-on-shutdown feature,” of the NEO-M9V Integration Manual UBX-21029776:

https://content.u-blox.com/sites/default/files/NEO-M9V_IntegrationManual_UBX-21029776.pdf

To configure this feature, users need to use the u-blox configuration tool u-center, which can be downloaded from the u-blox website.

For your convenience, I have included Section 3.9 Save-on-shutdown feature below.

====================================

3.9 Save-on-shutdown feature

The save-on-shutdown feature (SOS) enables the u-blox receiver to store the contents of the battery-backed RAM to an external flash memory and restore it upon startup. This allows the u-blox receiver to preserve some of the features available only with a battery backup supply present (preserving configuration, IMU calibration, and satellite orbit knowledge) without having a battery backup supply present. It does not, however, preserve any kind of time knowledge. Save-on-shutdown must be commanded by the host. The restoring of data on startup is automatically done if the corresponding data is present in the flash. Data expiration is not checked.

The following outlines the suggested shutdown procedure when using the save-on-shutdown feature:

With the UBX-CFG-RST message, the host commands the u-blox receiver to stop, specifying reset mode 0x08 ("Controlled GNSS stop") and a BBR mask of 0 ("Hotstart").
The host commands the saving of the contents of BBR to the flash memory using the UBX-UPD-SOS-BACKUP message.
For a valid request the u-blox receiver reports on the success of the backup operation with a UBX-UPD-SOS-ACK message.
The host powers off the u-blox receiver.

The startup procedure is as follows:

The host powers on the u-blox receiver.
The u-blox receiver detects the previously stored data in the flash. It restores the corresponding memory and reports the success of the operation with a UBX-UPD-SOS-RESTORED message on the port on which it had received the save command message (if the output protocol filter on that port allows it). It does not report anything if no stored data has been detected.
Additionally the u-blox receiver outputs a UBX-INF-NOTICE and/or a NMEA-TXT message with the contents RESTORED in the boot screen (depends on the configuration of the port and information messages) upon success.
Optionally the host can deliver coarse time assistance using UBX-MGA-INI-TIME_UTC for better startup performance.

Once the u-blox receiver has started up it is recommended to delete the stored data using a UBX-UPD-SOS-CLEAR message. The u-blox receiver responds with a UBX-ACK-ACK / UBX-ACK-NAK message.

CAUTION
Note that the save-on-shutdown feature works correctly only when the receiver has a valid time information when saving the SOS-BACKUP.