The source code of FSBL in platform can be
modified in place. Building platform again compiles the FSBL in platform. For Zynq UltraScale+ MPSoC, the FSBL source code is located
in <Platform>/zynqmp_fsbl and for Zynq-7000, the FSBL source code is located in <Platform>/zynq_fsbl. After you modify the source
code, build the platform again to compile the FSBL in platform.