Firmware Updates
All IoT solutions must allow device firmware updates. Supporting firmware upgrades without human intervention is critical for security, scalability, and delivering new capabilities.
AWS IoT Device Management provides a secure and easy way for you to manage IoT deployments including executing and tracking the status of firmware updates. AWS IoT Device Management uses the MQTT protocol with AWS IoT message broker and AWS IoT Jobs to send firmware update commands to devices, as well as to receive the status of those firmware updates over time.
An IoT solution must implement firmware updates using AWS IoT Jobs shown in the following diagram to deliver this functionality.
Figure 5: Updating firmware on devices.
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A device subscribes to the IoT job notification topic deviceId/jobs/notify-next upon which IoT job notification messages will arrive.
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A device publishes a message to deviceId/jobs/start-next to start the next job and get the next job, its job document, and other details including any state saved in statusDetails.
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The AWS IoT Jobs service retrieves the next job document for the specific device and sends this document on the subscribed topic deviceId/jobs/start-next/accepted.
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A device performs the actions specified by the job document using the deviceId/jobs/jobId/update MQTT topic to report on the progress of the job.
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During the upgrade process, a device downloads firmware using a presigned URL for Amazon S3. Use code-signing to sign the firmware when uploading to Amazon S3. By code-signing your firmware the end-device can verify the authenticity of the firmware before installing. FreeRTOS devices can download the firmware image directly over MQTT to eliminate the need for a separate HTTPS connection.
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The device publishes an update status message to the job topic deviceId/jobs/jobId/update reporting success or failure.
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Because this job's execution status has changed to final state, the next IoT job available for execution (if any) will change.
