If you have done a full build once with reference to the above article, you will be able to build a partial package and install only the packages created by that build. In other words, the entire build is not necessary when you modify something, so it can be confirmed quickly.
The package build method is as follows.
# make package/[package name]/compile
If you want to build with a more detailed log, you can do the following:
# make package/[package name]/compile V = s
The path for each platform may be slightly different, but you can see that the .ipk file is updated in the following location.
# cd bin/ar71xx/packages/base
If the modifications are limited to some packages, use package builds rather than whole builds.