I'm working on a project, where we need to change driver (module) in order to get some devices work.
If I compile just the module, I get error "invalid module format". Some people suggest to build kernel from source.
I tried that following your tutorial (https://bananapi.gitbooks.io/bpi-m3/zh/bpi-m3crosscompileteach.html). After compiling there is no "download" directory. There is an "output" directory, but there is missing boot.fex. Instead boot.fex is symbolic link to file which does not exist.
Can you please help me with this problem or give reference to some reading.
Best regards, Martin