@paradadf my network wasn't strong enough for the transfer of files. That's why it wasn't working. I put my usb drive in to pc where I had my roms and transfer them and they worked fine. But roms with multi bin files and one .cue wouldn't work so I just use eboot pdp instead. saves time and space to. Still cant get fds, dreamcast, 3do,pc engine CD are x86k to work.
I think I found the problem. I edited the name in es_systems.cfg famicom isn't a core so that's why it wouldn't launch. Even if the gui show you the options to configure a famicom.core somehow it doesn't exist. So the <name></name> tag need to be named nes. Same applies for super famicom.
I guess if I could find the core folder I might be able to copy that folder and have a new famicom core.
So in short to add famicom/super famicom to show in your US/EUR roms collection you need to:
edit your /recalbox/share/system/.emulationstation/es_systems.cfg
copy nes folder to /recalbox/share/system/.emulationstation/themes/recalbox-next/famicom
copy the svg art from jp to famicom/data directory
delete us/eu/jp sub folders
edit custom.xml and remove region section at the bottom of code
Last two steps might ot be needed but if you like to keep the code neat and clean you can do it.
@Thomas-Kings You must to close emulationstation before scrap with external tool, or kill -9 emulationstation process once scrap done, or perhaps works too, fast restart without save metada once scrap done. Otherwise emulationstation overwrite gamelist.xml when you shutdown or restart normally.
Subs just explained to you why it can't work : with such configuration, ES can't detect by itself which emulator to use for each rom, so it will be trying with one corresponding to either name or platform which will work only for fds rom in your example and then crash for all the others (fds emulator can't work for snes or n64 roms off course).
You may be able to do what you want by using a list of emulator in <name> and <platform> such as snes,nes,gd,fds but you will have to rewrite part of the emulatorlauncher.pyc python script