Felix Bau focused on maintenance engineering for the coolsnowwolf/immortalwrt repository, addressing a critical build issue in January 2025. He resolved a persistent 404 error affecting the kexec-tools package by updating the Makefile to reference the official GitHub source, restoring the reliability of the build process. This targeted fix, implemented using Makefile and build system configuration skills, ensured that continuous integration pipelines could consistently locate and compile the necessary sources. While no new features were introduced during this period, Felix’s work improved package maintenance and stability, laying a solid foundation for future releases and ongoing development within the project.