If you look at the commit that you cite you’ll see that my only contribution is fixing/rewriting the debian package scripts both to add improved error handling (we really really want to be careful when updating u-boot) and to work around an issue where dpkg can’t extract a new copy of SPL and u-boot.img over the old ones on a FAT32 filesystem, causing the package upgrade to fail. (hence the rm -f in preinst) This problem was noticed during testing and quickly fixed.
As de facto Debian packaging nerd on OSMC I do a lot of package script rewrites and fixes on existing packages to keep our package upgrade system as robust as possible and make sure that we maintain some common conventions and practices in the scripts. If you search for “Package Script” in the commits you should find dozens of commits from me across nearly all the packages.
I don’t have any detailed knowledge of how u-boot works beyond an overall conceptual overview so I would not be capable of making the changes that you imply anyway.