I was finally able to do the upgrade from 4.1.8 to 4.1.9
The issue was the many mods I had. And it didn't help by manually patching, either.
So the solution was to upload the unmodified 4.1.8 files, then upload the upgrade, then run it. That did the upgrade fine. Then went through and applied each mod, upload & test, until all were finished. And in the process fixed a couple of mod bugs
