buildroot/docs/manual/customize-busybox-config.txt

Customizing the Busybox configuration
-------------------------------------
[[busybox-custom]]

http://www.busybox.net/[Busybox] is very configurable, and you may
want to customize it. You can follow these simple steps to do so. This
method isn't optimal, but it's simple, and it works:

* Do an initial compilation of Buildroot, with busybox, without
  trying to customize it.

* Invoke +make busybox-menuconfig+.
  The nice configuration tool appears, and you can
  customize everything.

* Run the compilation of Buildroot again.

Otherwise, you can simply change the
+package/busybox/busybox-<version>.config+ file, if you know the
options you want to change, without using the configuration tool.

If you want to use an existing config file for busybox, then see
section xref:env-vars[].