I'm not sure if my previous question has been noticed since I put it in a comment. So I'll put it here instead.
Based on my understanding of HAB and HAB uImage Layout, uImage is authenticated as a whole by u-boot. and it seems to be the case for example API provided in a document.
Is there a code (and/or is it possible at all in HAB) for authenticating only a partial uImage since some parts of our image (at least at the end) should support a code update.