We present details on the new Level-1 Global Trigger at CMS for the upcoming high-luminosity operation of the LHC. Our focus is on the newly developed firmware, which employs a bottom-up generic approach to enhance menu adaptability and accommodate the increase in upstream data. We also highlight our efficient pipelining strategy that ensures excellent routability at 480 MHz. Furthermore, we discuss the firmware implementation for three prototypes targeting Serenity boards, together with their current and future testing and validation endeavours