Explore how to develop open-source firmware for IoT devices in this 38-minute conference talk from the Linux Foundation's Open Source Summit. Learn about implementing Zephyr RTOS as an alternative to closed-source solutions for connected home devices, with a focus on creating more secure, robust, and privacy-respecting smart devices. Discover the process of reverse-engineering existing hardware and developing custom Zephyr firmware for a connected light bulb project. Examine the technologies available for building IoT devices that don't rely on cloud servers and maintain user privacy. Gain insights into the practical challenges and solutions involved in creating open-source alternatives to commercial smart home products, including hardware analysis, firmware development, and the implementation of local connectivity protocols.