You can try this option steps. You'll add a new empty branch (add readme.md) to git build, I'll be able to clone it, add my changes to the new branch, and send a merge request.
Between the existing system of images for models without built-in memory (eMMC) and TV boxes, there is a fundamental difference in the principle of starting the system. I wouldn't want to break the existing system. For TV boxes do not need u-boot, they can use the standard u-boot, it is safe for users and much easier. Therefore, I propose separate branches, so they do not interfere with each other.