What’s the best way to do firmware updates over the air (FOTA) for trackers?

LTE-M / NB-IoT (Monarch)
1

Hello,

I’m interested in your recommendations for my application FW and what you offer for the modem FW.

Thanks,

Brian

1 Like
2

There are two ways to perform Firmware Over The Air (FOTA) updates:

  1. Network-Initiated FOTA:

    • Supported by Verizon and part of the GM02S certification.

    • For other carriers, supported through a partner, AVSystem.

    • Reference: “Monarch2 - LwM2MFOTAService - Rev.1.pdf”

    • Note: You do not need your own infrastructure for this method.

  2. Device-Initiated FOTA:

    • Simpler to implement but requires your own infrastructure.

    • AT Command: +SQNSUPGRADE(it supports HTTP/HTTPS, FTP/FTPS)

    • References:

      • AT Command Reference Manual: “Monarch2-ATCommandsReferenceManual-LR82-Rev.3c.pdf”

      • Application Note: “Monarch2-ModemAppBasics-Rev.4.pdf” (section 13: FOTA management)

3

Dear Brian,

Greg has already outlined the two supported approaches for performing firmware updates on the modem. In addition to that, I’d recommend planning your overall update strategy with a clear distinction between:

  • Application firmware updates (your code running on the MCU/application processor)

  • Module firmware updates (the Sequans modem itself)

For your application firmware in particular, a few best practices can help ensure smooth and reliable updates:

  • Use delta updates when possible to minimize data volume.

  • Implement resume/retry logic so that if the connection drops, the device can continue from the last received chunk instead of restarting.

  • Always verify the update signature before applying, leveraging secure boot mechanisms. (which you can leverage on the module for the module FW update)

  • Apply updates under safe conditions only (e.g., battery above a threshold and device idle).

  • Design a rollback path, keeping a last known good firmware image in flash in case the update fails.

  • Be mindful of NB-IoT limitations: large updates in the MB range are not practical. Try to keep update sizes below ~200–300 KB whenever possible.

These considerations will make your update process more resilient in real-world deployments and save you troubleshooting effort later.

Best regards,

Jeremy