Aha! I see it was failing to find the BIOS - I didn't consider that because literally every other game has worked perfectly. dc_boot.bin and dc_flash.bin were both in there, but they were the wrong files. Have now replaced them and everything's peachy. Cheers for the tip :)
I was doing everything right with the m3u file but I forgot that when I update the emulator config file in Attract Mode to include m3u via the network I need to reset the whole system for the changes to update. Bit of a "d'oh" moment really. When it was previously loading only one disc it will have been picking up the .chd files themselves as they were similar in name.
There are a few - glaring - errors in your configurations:
there is no /opt/openarena folder in a RetroPie installation, so your emulators.cfg files are wrong. You copied that from your previous installation, it's not compatible to the RetroPie installation, no wonder they don't work.
Reicast doesn't support Naomi/Atomiswave ROMs and there is no lr-reicast in RetroPie (it's the former name for lr-flycast).
If you have created custom folder for Naomi/Atomiswave ROMs, then you should install lr-flycast and then copy the emulators.cfg, from the dreamcast system to your new system configuration. Make sure you have a corresponding retroarch.cfg in each config folder, containing
Gotcha. That's essentially what I did, since I have my ROMs on a USB drive, I just copied those cfg files. I didnt realize the dingus that had created that previous installation changed the directory structure (yet another plus to abandoning it).
Well I'm on the right path now (get it?) to fix it. Thanks for the help, yet again.
@andykt76 great tutorial thank you for doing this. I followed your steps for the PS1 lightgun setup and now I’m stuck on the guncon calibration screen in time crisis. I can’t seem to get it to move past this step, any suggestions or did I take misstep?
@mitu I did a lot of reading around in those docs, but since I didn't require a user/pass for access I didn't know how much of that I should cut out of the line so I browsed forums until I found an example of someone doing what I was trying to.
Duly noted, though. Just another thing added to all the stuff I've learned about this stuff in the last couple months. After fixing that, Daphne works as well for me. I knew it was going to be some little minute detail. Thanks again, you're a lifesaver.