Explore reverse engineering techniques for Embedded Controllers (EC) in recent Lenovo Thinkpad laptops in this Black Hat conference talk. Delve into attacks from EC trusted boundaries on main platform firmware (BIOS) and learn how to bypass Intel BIOS Guard technology in Lenovo's specific implementation. Understand hardware security boundaries, EC firmware update processes, and the impact of EC update authentication bypass. Examine Lenovo Thinkpad EC update headers, signature checks, and disclosure timelines. Gain insights into Intel BIOS Guard, including its structure, hardware support, and execution flow. Analyze BIOS Guard Directory, Platform Data Table, and Update Package components. Compare signed and unsigned operations with BIOS Guard scripts to enhance your knowledge of firmware security vulnerabilities and mitigation strategies.