Is it still using a Broadcom CPU that requires you to sign an NDA in blood to get a datasheet for the part?
I admit this is one f*cking problem with the RPis. I'm sure this is part of what enables them to release them so cheap (they had a good deal with Broadcom), but this is really annoying for any "serious" use IMO.
Of course this is even more annoying if you ever want to use those boards/modules "baremetal", or adapt some OS for them that's not officially supported.
I started writing baremetal support code for the RPi4 a few months ago. Going baremetal would certainly allow a lot of very nice things. But beyond basic support, I was quickly limited due to the fact access to official documentation was almost impossible.