After you have configured your hardware project, the PetaLinux project requires a hardware description file (.xsa file) with information about the processing system. You can get the hardware description file by running Export Hardware from the Vivado® Design Suite.
During project initialization (or update), PetaLinux generates a device tree source file, U-Boot configuration header files (if auto config enabled for U-Boot), and enables the Linux kernel drivers (if auto config enabled for Linux) based on the hardware description file. These details are discussed in PetaLinux Project Structure.
For Zynq® UltraScale+™ MPSoC platform, you need to boot with the Platform Management Unit (PMU) firmware and ATF. See Generating Boot Components for building PMU firmware and ATF. If you want a first stage boot loader (FSBL) built for Cortex™-R5F boot, you have to build it with the Vitis™ software platform because the FSBL built with PetaLinux tools is for Cortex-A53 boot. For details on how to build the FSBL for Cortex-R5F with the Vitis software platform, see the Zynq UltraScale+ MPSoC: Software Developers Guide (UG1137).
For Versal platforms, boot with PLM, PSM and ATF. See Generating Boot Components for building the PLM, PSM, and ATF.