Worked on the srwi/qmk_firmware repository to enhance keyboard firmware by expanding the One-shot Layer (OSL) functionality. Developed a feature that allows OSL to chain with other layer-switching keys such as MO, TG, TO, DF, and LT, enabling more flexible and dynamic layer management for custom keyboards. Implemented automated tests in C and C++ to validate the correct behavior of chained activations and to ensure that releasing an OSL does not disrupt other active layers. Focused on embedded systems and firmware development, this work improved reliability and test coverage for advanced keyboard customization and dynamic layer switching scenarios.