Explore a comprehensive conference talk that delves into the security challenges of Arm Cortex-M Microcontrollers (MCUs) and the TrustZone-M technology. Learn about the limitations of CPU-centric security in TrustZone-M and the potential vulnerabilities in modern MCU-based Trusted Execution Environments (TEEs). Discover how to bypass CPU-level isolation primitives and understand the design of TEE core mechanisms for enhanced protection. Witness a live demonstration of an exploit that breaches TEE isolation boundaries to retrieve cryptographic keys from Secure Partitions and the Trusted kernel. Gain valuable insights into the complexities of implementing system-wide isolation in TrustZone-M systems and the importance of understanding PSA isolation levels for securing IoT devices at scale.