During December 2025, Qingmey Tang contributed to the levizh/rt-thread repository by addressing a critical low-level issue in AArch64 architecture support. Focusing on embedded systems and assembly language, Qingmey stabilized callee-saved register usage by replacing register x8 with x19 in key kernel components. This targeted change improved function call reliability and ensured alignment with ARM64 calling conventions, reducing the risk of ABI inconsistencies and future regressions. The work demonstrated a disciplined approach to change management, with a single, well-documented commit that enhanced maintainability and prepared the codebase for safer optimizations and platform updates in embedded environments.