Currently uic offers the possibility to
- replace files in the installation area with supplied ones (recipe path
files)
- delete files in the installation area (recipe component
files.remove)
If a file instead must be modified, the only way to do this, is to write a post_customization or chroot_post_customization hook that does the job.
In order to quickly modify files, a mechanism based on unified diff format files located in the new recipe path patches should be implemented.