Over the past decade the Unified Extensible Firmware Interface (UEFI) has become the primary standard for boot firmware. However, the complexity of the UEFI spec and the myriad of implementation choices can be confusing to even experienced developers. Fortunately, there are a growing number of open source UEFI implementations for different architectures, making it easier to explore the world of firmware. This session will provide an overview of UEFI and show working examples based on two maker platforms: BeagleBone Black and the Aaeon’s UP Squared board. Everything from “lightweight” implementations to full UEFI stacks will be examined, using a variety of open source projects (TianoCore, U-Boot, coreboot, and Slim Bootloader). Questions this talk should answer: -What is the goal of the UEFI spec and what are some popular implementations? -How do I replace the stock firmware on my board with open source UEFI? -What are the benefits of running TianoCore rather than something more lightweight like coreboot or Slim Bootloader? -How does U-Boot implement UEFI, and how does it differ from EDK II?