System function to return MAC address in Android?

Question

Android

In my Android, the mac address changes dynamically when WiFi is turned on.
There is no possibility to change it by well-known methods (in the console) (returns an error).
I'm thinking of changing the system function that generates this dynamic mac address so that it always generates the same one, or reads from a file.
The question is - how difficult is this task, what is needed for this?

Firmware - yes, source codes, of course, no.
I assume that any command line utility that returns a poppy address only calls a system function, which is possibly compiled in a separate library file for working with the network, for example.
And you can, for example, reverse-engineer this file or replace it with another one.