Hello. As stated here [1], in order to use HATs, and overlays in general on the Raspberry, you have to remove the /boot/dtb symlink. You know, I'm not an expert. What does this mean? Why do you need to do that? Why this symlink is here by default? And, there are some downsides by removing such symlink?
[1] https://fedoraproject.org/wiki/Architectures/ARM/Raspberry_Pi/HATs
Thanks, A.