Removable Memory Key to IoT Firmware Updates

When Over The Air (OTA) Updates Fail

When designing an IoT device, consideration should be given on how to successfully implement secure remote firmware updates.  Over The Air (OTA) updates can be a challenge for remote IoT devices that are connected using cellular radios/modems.  The embedded design should not only strive to make the OTA update process as robust as possible, but should also allow for an alternative firmware update method for those devices that fail to update OTA.  This white paper examines three manual update options, looking at cost, customer inconvenience and risk.

Removable Memory is the Key!

Removable memory is an ideal "Plan B" for updating remote IoT devices when an OTA update fails, providing the lowest cost, customer inconvenience and risk.  Additionally, removable memory can be used for a host of other applications.  The white paper discusses the challenges of OTA updates, looks at manual update options and explains the benefits of using removable memory devices for this and other useful functions.  The paper also includes bonus content that explains, why OTA updates can be a challenge with cellular-based devices and provides helpful design hints to make OTA updates as reliable as possible.


Table of Contents

  1. Introduction
  2. Anatomy of an OTA Firmware Update
    1. Phase 1: All of the devices have the old firmware
    2. Phase 2: Most devices have received the firmware and have started updating
    3. Phase 3: Most devices have successfully updated their firmware
  3. Using Removable Memory for Updating Firmware in IoT Devices
    1. Which Memory Device to Choose
    2. USB Flash Drives
    3. Memory Cards
    4. Proprietary Memory Devices
  4. Other Uses for Removable Memory in IoT Devices
    1. Security Functions
    2. Data Logging
    3. Enable Custom Functions
  5. Conclusion
  6. About the Author
  7. Appendix A - Why is it so difficult to successfully updat the firmware on 100% of remote devices?
  8. Appendix B - Design hints for OTA firmware updates, with weak signals and unreliable bandwidth

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