Those HAT-modules cannot handled with "Static device tree" -structure, and "Device tree overlay" -batch system is used for Rasberry.
U-boot supports DTO, but Linux not, so it's difficult to say how it works, but I can guess, that U-boot modifies Device tree file and transfers it as static structure to kernel:
(DTO is on 23 min. point of video)
https://www.youtube.com/watch?v=Nz6aBffv-Ek