That IS the reason, unfortunately
I was trying to do just as you said first because it seemed like the easiest way to take care of it, but every time I'd try to go into dop-mii and reinstall the System Menu it'd tell me that it couldn't open certain .wad files from the SD card- and I can't use the download from NUS option because I would have to connect to the internet to do so, which is the whole thing I'm trying to fix smh. It's been a very long, vicious cycle that I've been trying to fix for the past 6 hours honestly. I just ignored the fact that it said that file was missing from the initial ModMii first because I saw someone on another thread say that I didn't really need it, and plus the guide had an alternate option to patch the IOS anyway, but after exhausting every option everyone else had told me to try, I figured it must be the fact that I'm missing that file; so I went to try the downgrade option instead of pick the same version in ModMii but it still came up missing that file, so here I am again drowning in a puddle of my own tears
