It has been a while since the last post about the missing footer banner for GBA games, so I'm not sure whether this is still a thing or not.
Nevertheless, after repacking some of the cias, I recognized that the language of all banner models is set to USA_EN, therefore it won't appear on European systems at all. If the cia is manually repacked with adjusted models (e.g. EUR_GE for German) everything works fine. This can be achieved with tools like
ba-GUI-nnertool (Can't hyperlink since I'm new. You'll find a GBATemp thread if you google it). For further instructions, relate to the HOW TO.pdf in the downloaded archive (last two pages). However, this process is tedious and takes a fair amount of time.
I'm aware that
@Asdolo is pretty busy rn, however this might help to fix the issue in the near future.