6.3 Device Firmware Upgrade Over Bluetooth® LE

Introduction

One of the highly important features of wirelessly connected devices is the capability of Over-The-Air Device Firmware Update (OTA DFU). The end-users increasingly demand this functionality to:

• Address issues and security vulnerabilities.
• Ship products to market faster and have the option of delaying lower priority features and rolling them out to devices in the field.

The PIC32WM-BW1 family of devices supports OTA upgrade through Bluetooth® Low Energy (Bluetooth® LE).

Microchip defined OTA profile and service enable firmware upgrades over the BLE link using Generic Attribute Profile (GATT). The Bluetooth LE OTA protocol defines the communication between the OTAU target and OTAU manager. A mobile device (iOS®/Android™) or any Bluetooth LE device that implements the OTA GATT client protocol can serve as the OTAU manager to transfer the upgrade firmware to the OTAU target. The OTAU target implements the OTA GATT server protocol to receive the new firmware image.

Secure BLE OTA DFU Process

With the increasing popularity of OTA DFU capability in IoT devices, these devices are getting exposed to vulnerabilities and security threats. Therefore, it is important to ensure that the device’s OTA DFU process is secure and reliable. To send an upgradable image reliably and securely, sign and encrypt the image.