The hardware itself is flexible and relies on software for things like calibration, setting frequencies, and setting power.

> Seems like security by obscurity.

There are legal standards to meet around protecting the system from users modifying things like output power. They don’t literally say that the source code must be private, of course, but keeping it closed source makes it much easier to demonstrate that you were not making it easy for people to exceed the regulatory limits.

If you document the registers for setting output power (for example) then you’re giving the end user a roadmap for changing output power.

I don't know, I don't think there are many open-source third-party firmware implementations for these kinds of chipsets out there, so it seems pretty well obscured.

Exactly my thoughts. To avoid out-of-regulation tweaking coudn't they just allow signed code to run? How can I be sure that this closed for, i.e. surveillance reasons? One can publish the source code and still prevent misuse afaik.