It looks like the problem were some archives being misnamed for some reason but I got them fixed and working now!
It doesn't seem to be any other problems so far.
I've been trying to undub an EUR version of the Inazuma Eleven GO! Shadow game but I couldn't find much info on how to do it and I'm a novice so I'm asking for help!
I've been using HackingToolkit9DS to extract both games (JP and EUR) and I read that I had to exchange the Romfs files because...
I shared this thread on twitter! I hope someone offers some help!
If needed, I can test in an old!3ds. Maybe in a new!3ds xl too! (If my sister lends it to me.)
I am looking forward to this project!
Good luck!