Hi there, if you are talking about the xdelta patch that redoes EBOOT.bin and SHARED.bin you shouldn't need to use the Xdelta patch, and just run build.py as this also runs the assembly code which runs the code from Mod.asm and redoes it in the same way that patch was originally made. (I may be mistaken here, since I do not know if anything else was originally added into that delta patch, but It successfully works without it.)
Do you have the Mod.asm assembly file? keep in mind if you do, it is probably a very old version of it that has had some tweaking since then as well as the building tools. At this time I cannot post the latest assembly code since it is in an unfinished state. I have been pretty busy on something for a good while now, but I plan to pick back up and finish it all in the coming week or so. If the build still fails then throw a message on here, and I'll help rectify it.
A reason we don't throw up a patched ISO is because of the reason with legality for one mostly, and secondly It's not bug free totally yet. The end goal is to make a patch that you can add on to your existing original ISO.
Thanks, Six.