I had to manually edit the download link too.
I did what you suggested and managed to make it work! Thank you so much for your advice, i really hadn't thought about using a former file.
P.S: the exact file to replace is the file "3" in .../Encounter Type/679 Build/a/0/1, and it should be put in /luma/titles/000400000011c400/romfs/a/0/1/