The Platform Management Unit (PMU) in AMD Zynq™ UltraScale+™ MPSoCs is located within the Low-power sub-system. The PMU consists of a MicroBlaze™ processor which loads executable code from 32 KB ROM and 128 KB RAM into flat memory space. The PMU controls the power-up, reset, and monitoring of resources within the system including inter-processor interrupts and power management registers. The ROM is preloaded with PMU bootROM (PBR) which performs pre-boot tasks and enters a service mode. PMU_FW must be loaded to provide advanced system functionality for each of the AMD supported use-cases. This chapter explains the features and functionality of PMU firmware developed for Zynq UltraScale+ MPSoC.