Using u-boot for ZYNQ to load Linux doesn't need users to understand how in low level it works, especially if PetaLinux is used. When bringup for a board is needed, some configuration files needs to be updated and PetaLinux can help with the most of the work. If more customization is needed, then the deeper understanding of u-boot would be needed.
- Debugging U-Boot With SDK
- U-Boot: Hush Shell, Scripting
- U-Boot FIT Images