What is the procedure to add some modules that were left out of the previous configuration of a custom kernel build? I have had this question for awhile but have just been doing the whole 'make-kpkg kernel_image modules_image' over again.
I tried 'make -C <* path to Linux *> M=$(pwd)' per the kernel doc (kbuild) but it didn't build the module(s) I wanted, just created a 'built-in.o'.

In this instance, I forgot to configure MAC80211 and wireless support for my
Broadcom 4318 card. So I went back and configured the needed functions as modules, then tried the short make method but no B43.ko was created. Now I just did another make-kpkg kernel_image modules_image and it looks like it's compiling the whole thing again which I'm sure is a waste of resources (even though I have ccache and distcc wired up).

Any help on this is greatly appreciated, thanks in advance!

read this

I figured out the reason for building 'built-in.o' was because the
wireless functionality was not so simple as just building the modules in the subdirectory because the configuration pulled in
some other config items that were required for the whole subsystem, and those items were built into the kernel.