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Over-the-Air Update

Overview

Over-the-Air (OTA) Update is a method for delivering firmware updates to remote devices using a network connection. Although the name implies a wireless connection, updates received over a wired connection (such as Ethernet) are still commonly referred to as OTA updates. This approach requires server infrastructure to host the firmware binary and implement a method of signaling when an update is available. Security is a concern with OTA updates; firmware binaries should be cryptographically signed and verified before upgrading.

The Device Firmware Upgrade section discusses upgrading Zephyr firmware using MCUboot. The same method can be used as part of OTA. The binary is first downloaded into an unoccupied code partition, usually named slot1_partition, then upgraded using the MCUboot process.

Examples of OTA

Golioth

Golioth is an IoT management platform that includes OTA updates. Devices are configured to observe your available firmware revisions on the Golioth Cloud. When a new version is available, the device downloads and flashes the binary. In this implementation, the connection between cloud and device is secured using TLS/DTLS, and the signed firmware binary is confirmed by MCUboot before the upgrade occurs.

  1. A working sample can be found on the Golioth Zephyr-SDK repository

  2. The Golioth OTA documentation includes complete information about the versioning process

Eclipse hawkBit™

Eclipse hawkBit™ is an update server framework that uses polling on a REST api to detect firmware updates. When a new update is detected, the binary is downloaded and installed. MCUboot can be used to verify the signature before upgrading the firmware.

There is a Hawkbit Direct Device Integration API sample included in the Zephyr Management Samples section.

UpdateHub

UpdateHub is a platform for remotely updating embedded devices. Updates can be manually triggered or monitored via polling. When a new update is detected, the binary is downloaded and installed. MCUboot can be used to verify the signature before upgrading the firmware.

There is an UpdateHub embedded Firmware Over-The-Air (FOTA) sample included in the Zephyr Management Samples section.

SMP Server

A Simple Management Protocol (SMP) server can be used to update firmware via Bluetooth Low Energy (BLE) or UDP. MCUmgr is used to send a signed firmware binary to the remote device where it is verified by MCUboot before the upgrade occurs.

There is an SMP Server Sample included in the Zephyr Management Samples section.

Lightweight M2M (LWM2M)

The Lightweight M2M (LWM2M) protocol includes support for firmware update via CONFIG_LWM2M_FIRMWARE_UPDATE_OBJ_SUPPORT. Devices securely connect to an LwM2M server using DTLS. An LwM2M client sample is available but it does not demonstrate the firmware update feature.