Tried the same thing but instead using the py modinstall.py 0xOFFSET.FILETYPE modinstalling on the arc file to install the mods. Put them in the correct directories on SD without modifying them. Got the Data.arc, romfs, exefs folders, etc. Ultimate from the store, brand new because FOUR different SSBU dumps were giving me the same error. I just got a LEGITIMATE cartridge copy of Super smash Bros. (Even tries the 1.1 method of modding it.)