# Device Firmware Update (DFU) Guide

This group of topics provides information about the tools, protocols and firmware required to perform wired and Firmware Over the Air (FOTA) firmware updates using the RSL15 Evaluation and Development Board. This guide provides an overview of the sample bootloader and its usage, includes details about the FOTA firmware images and tools, walks you step-by-step through your first firmware update using a pre-configured sample application, and shows you how to modify an existing application to support FOTA updates.

These FOTA topics are intended for firmware developers who are designing and implementing RSL applications with FOTA capability. Updating firmware is also possible with a wired connection using UART or SPI, as described in the Bootloader topic.