No, that's not correct. The device running MAME 2003 plus is the Legends Flashback, which emulates some arcade games and Atgames is using a custom core with only the licensed games enabled. They also have their own emulator to load the cores so we don't have retroarch.cfg.
While 'playing' with this device, I've added support to MAME 2000 core, and it has been working well except for games requiring to read the nvram to run (Williams games). I've seen the code to set the directories in MAME 2000 is different from MAME 2003 (plus), causing the core to create a directory "(null)" if the 'front-end' is not passing the content_path. I could copy the newer code and include into MAME 2000. I've attached libretro.c with the changes if you want to validate or potentially include in the repository.
With that said, I've been able to compile a working MAME 2000 core with this fix implemented, and it is working fine. With the right hardware and packages it's not that difficult to build it. The only 'hack' I'm still using in this core is to 'mask' zip files as 'zim'. It is needed to avoid conflict with the original core in this device, the menu in this device load the cores based on file extension. I've started to look at the code to read zip files but it was too difficult to change it in the code so I've just 'hacked' the extension with a hexadecimal editor. I may try to improve this later.
Anyway, now there is a 'clean' solution to run the Williams games and arcade games saving data to nvram. If anyone want to try it, I'm updating the first post with the link to this update, which I think it will be the definitive update for this device with the current firmware version (v2.6)
Xdqwerty
