You'll need to make some changes to '/etc/preinit.d/b0000_defines'. Change the gamepath to '/usr/share/games', copy the games from '/usr/share/games' to '/var/lib/hakchi/rootfs/usr/share/games' and reboot your SNES Mini.
This will fix overmounting of /usr/share/games (while keeping original games), and you'll be able to write there. After that just FTP your files so the injected folders look like this:
View attachment 101093
Well, anyone can. Just add the header/footer to ROM and edit .desktop and .png