Remote in-the-field IoT devices communicating via LoRa radio links occasionally require updates or bug fixes. To do this, new firmware must be installed on the IoT device. If this capability cannot be carried out reliably and effectively over the same channel used for data communication, these updates will be slow, complex and costly.
 
FUOTA capabilities (Firmware Update Over The Air) are therefore essential to safeguard the future of LoRa devices, even if LoRa is used for updates as a power-saving technology for connecting IoT devices. The LoRa Alliance has published three FUOTA LoRaWAN application specifications (v1) that support and standardize FUOTA: Application Layer Clock Synchronization, Remote Multicast Setup and Fragmented Data Block Transport. These relate to time synchronization, the sending of messages to groups of end devices or the splitting of data files.
 
By supporting firmware updates according to these specifications, I-CUBE-LRWAN enables STM32 developers to use FUOTA for STM32L4 microcontrollers. The advantages of the Secure Boot and Secure Firmware Update solution (X-CUBE-SBSFU) are combined with an open-source crypto library. The update process is carried out using a secure procedure to prevent unauthorized updates or access to confidential data stored on the IoT device. The package includes the LoRaWAN stack with hardware abstraction layers and sample code for STM32L0-, STM32L1-and STM32L4 microcontrollers. A test application for LoRaWAN certifications is also part of the package.
 
ST's I-CUBE-LRWAN software can be used together with LPWAN development boards and sensor expansion boards from the STM32 Nucleo system, for example with the LoRa nodes in the P-NUCLEO-LRWAN2 and P-NUCLEO-LRWAN3 Developer pack.
The latest I-CUBE-LRWAN Expansion Package with FUOTA support for STM32L4 can now be downloaded free of charge from www.st.com/i-cube-lrwan. It is interoperable with various network servers, for example from Actility and Senet.