The following example shows you how to edit FSBL/PMUFW source files.
setws workspace
app create -name a53_app -hw zcu102 -os standalone -proc psu_cortexa53_0
#Go to “workspace/zcu102/zynqmp_fsbl” or “workspace/zcu102/zynqmp_pmufw” and modify the source files using any editor like gedit or gvim for boot domains zynqmp_fsbl and zynqmp_pmufw.
platform generate