Worked on the renesas/zephyr repository to enhance the stability and security of OpenThread radio key handling within embedded systems. Focused on firmware development using C, the developer addressed a critical issue in MAC key initialization that previously led to undefined behavior and RX security errors. By ensuring proper lifetime management of MAC key IDs and initializing relevant variables, the patch prevented potential reference errors and mitigated security risks in parent/child radio scenarios. The targeted fix improved code maintainability and reliability, demonstrating a methodical approach to embedded C programming and robust firmware practices, with attention to both security and long-term code quality.