Ok, thanks. I'll see if JKSM still works on 11.4. I'll probably edit this post and add the save if it works.
Edit: Ok, so it froze with a green bottom screen twice in a row... I'd expect red if it were to not work. Maybe I'm just unlucky...
I'll try extdata_dump...
...
AM_GetTitleCount() failed: 0xd8e007f7
Well, thanks for offering, but it just so happens that I was forced to install 11.4 after finding a new way to soft-brick in pursuit of CFW.
(The .FBI installer can be used to install system updates, oddly enough. In my case it was 11.0, which apparently didn't support badges...? I still want to know what the 0.23.? and 25.?.? would do, though... probably would have hard-bricked my 3DS xD)