Open Source Summit North America 2025

The FUOTA (Firmware Update Over-The-Air) specification(s) from LoRa Alliance make up the framework that underpins the critical task of firmware updates of end points (typically battery operated sensors and actuators) that communicate using the LoRaWAN protocol.

The fundamental limitation of the FUOTA specification, as it exists today, is that it does not expect Firmware Artifacts to exceed a few hundred KB in size. With the increasing adoption of the Zephyr RTOS, along with more sophisticated capabilities being added to the end device, artifact sizes have quickly grown to 500 kB (and beyond). This limitation quickly starts to have a real impact, especially as the cost of doing so called 'drive by' updates (using BLE or other higher throughput transports) can get prohibitive.

We present a novel solution to this problem, leveraging the existing and well supported Device Firmware Update (DFU) specification.

In our solution, the LORAWAN protocol becomes another type of SMP transport (along with the already supported Shell, Bluetooth and UDP). We have extended the open source smpclient library from intercreate, as well as the open source LBM stack from Semtech to achieve this.