Select the fsbl_a53 under FLOW and Build.
The FSBL executable is now saved as fsbl_a53/build/fsbl_a53.elf. In this tutorial, the application name fsbl_a53 is to identify that the FSBL is targeted for the APU (the Arm Cortex-A53 core).
Note: If the system design demands, you can target the FSBL to run on the RPU.