Help Needed with Multi-disc Sega CD Games

[RetrOkada]

Hello Everyone,

I would like to be able to add Night Trap and Prize Fighter to my Sega CD collection, and both games have two discs.

For Playstation games, this is fairly easy; create an .m3u file which references the .cue files of each of the discs. This allows for disc swapping, using the "Disc Index" option within the RGUI menu.

Unfortunately, when I added such games to the "segacd" folder, they did not show up in my Recalbox.

Is disc-swapping possible for Sega CD games under Recalbox; is this supported by either Picodrive or Genesis Plus GX? If so, is .m3u the best way to go?

I attempted to add the .m3u extension to the Sega CD section in /recalbox/share_init/system/.emulationstation/es_systems.cfg. However, I have thus far been unable to do this. Using "Nano", I am able to open the file directly through a Terminal on my Recalbox. However, when I attempt to save/write out, I receive a filesystem read-only error. I tried "mount -o remount,rw /recalbox", but this seemingly had no effect.

I am running Recalbox from an SSD, as I am using the NesPi4 case. As such, I removed the SSD, and connected it to my MacBook, using a USB-C to SATA adapter. Due to MacOS being unable to read Linux filesystems — to my knowledge — I installed the trial of extFS for Mac. However, the only additional volume found was called "Overlays". Neither this, nor the "Boot" or "Recalbox" volumes, contain a "share_init" folder that I can find.

I then tried to access the drive from a Ubuntu virtual machine, through VMWare Fusion Player; this didn't work either. When I attempted to connect the device through the Virtual Machine menu, I received the following message:
"The device was unable to connect to its ideal host controller.
An attempt will be made to connect this device to the best available host controller. This might result in undefined behavior for this device". I clicked "Okay" anyway, but the drive didn't show up under "Files" in Ubuntu.

I am unsure what else to try. Presumably, if I SSH through Ubuntu, the filesystem will still be read-only? I do have another Raspberry Pi on which I run Homebridge. How about if I purchase a USB to SATA adapter, connect my Recalbox SSD to the other pi, and attempt to amend es_systems.cfg in this way?

Would really appreciate some insight/guidance; even if Sega CD disc-swapping is currently unsupported, at least I know not to pursue it further.

Any help gratefully received.

[Zing]

@retrokada

• https://forum.recalbox.com/topic/21249/swap-disc-in-sega-cd-games
• https://www.reddit.com/r/RetroArch/comments/ip3aaz/switching_multi_disc_sega_cd_games_on_3ds/

[RetrOkada]

@zing Thanks for your reply.

The first of these links mentions that disc swapping for Sega CD works the same as for Playstation.

All of my multi-disc Playstation games are loaded through .m3u files, as recommended in the Recalbox documentation, and they all work perfectly:
https://recalbox.gitbook.io/documentation/emulators/consoles/playstation-1

When I attempt to achieve the same result with Sega CD games, the .m3u files are not displayed. So, even if Genesis Plus GX does support .m3u files, it seems that Emulationstation is not configured to display them for Sega CD games.

I was able to open the es_systems.cfg file, and can verify that .m3u is not listed under "Extensions" in the Sega CD section.

A further search of the Recalbox forum returned the following result:
https://forum.recalbox.com/topic/17186/problem-custom-es_system-cfg/3?_=1633475250525

From this topic, it seems as though editing of es_systems.cfg is no longer supported. As such, it may not be possible to have .m3u files displayed by either of the Sega CD cores. Is this correct? If so, is there another way I can achieve this?

I believe .chd was listed as a valid extension. Can disc-swapping be accomplished through this format?

Many thanks again.

[Zing]

@retrokada

From this topic, it seems as though editing of es_systems.cfg is no longer supported. As such, it may not be possible to have .m3u files displayed by either of the Sega CD cores. Is this correct? If so, is there another way I can achieve this?

ARRM allows you to change the supported extensions:
https://forum.recalbox.com/topic/11850/soft-arrm-another-recalbox-roms-manager

[RetrOkada]

Hi @zing, thanks for the link.

That's a really powerful tool, works well.

One thing I learned is that it seems to be the gamelist.xml, rather than Emulationstation itself, which dictates the file extensions which are displayed.

Using ARRM, I was able to generate .m3u files for both Night Trap and Prize Fighter. I did this by highlighting the entries for the separate discs, for example Night Trap Disc 1 and Night Trap Disc 2, and clicking "Generate .m3u". The file was created, and ARRM conveniently hid the separate .cue files; that's a really nice feature. I then saved the changes to the gamelist.xml file, replacing the existing version with the one created by ARRM.

Unfortunately, though, the games don't actually run on Recalbox. The entries do appear in the list of games but, when I launch one, it doesn't load, instead kicking me back out to ES. I have tried running them with both cores; LR_Picodrive and LR_Genesis Plus GX. The only difference with the latter is that it sometimes fails to revert to ES, instead remaining on a black screen. I am able to manually return to ES with Hotkey+Start, as expected.

So, essentially, while .m3u files are now, seemingly, being displayed, they can't actually be played.

I have checked my bios files, and everything seems fine; under "bios Checking", Recalbox shows everything as green. I have "bios_CD_EU", "bios_CD_US", and "bios_CD_J" all present.

I have checked the contents of the .m3u files, and they seem to be pointing to the correct .cue files, in the correct order. I have also verified that they are in plain text.

I have found that the separate discs do run properly on Recalbox; IE, I can load Disc 1 on its own.

Are there any other things I can try?

Cheers.

[Zing]

@retrokada

Are there any other things I can try?

Are you sure the problem is not with the ROM? Suppose there is more than one version of the game, and you have disk 1 of one version and disk 2 of another version, there would be incompatibility between the versions and you wouldn't be able to make it work (it's just a possibility).

I've seen in some posts past users with other 2 disc games playing disc 1 all the way, then renaming disc 2 to disc 1 and continuing the game (although this is not the ideal solution)...

I still recommend you try it with a ROM in ISO format, or CHD format, I've seen reports from users saying they were only able to make it work with the game in ISO.

[RetrOkada]

@zing Thanks for your reply, I've finally got around to playing with this further.

I'm pretty sure the roms should be compatible. Both discs are the European versions; They are standard Sega CD versions, not CD-32x as I've read that these definitely don't work for disc-swapping.

I managed to convert the .bin/cue images to .iso format by mounting them with Daemon Tools. The resulting .iso files ran correctly when I loaded them into Recalbox as separate disc 1 and disc 2 entries. Unfortunately, I still couldn't get the .m3u playlists to run under either of the Sega CD cores. Again, I generated the .m3u files using the button in ARRM, and verified that they are formatted correctly.

I haven't yet tried the roms in .chd format. I will need to devote some time to it, as I will need to learn the chdman tool.

Again, really appreciate all your suggestions. My suspicion is that I won't be able to get Sega CD disc-swapping to work; luckily for me, it's not a priority. Playstation games are far more important to me, and those work like a charm. Still, I'll have a go with Sega CD games in .chd format, just to see if it works.

Thanks for all your help.

[Zing]

@retrokada

I still couldn't get the .m3u playlists to run under either of the Sega CD cores.

I know that the topic below does not talk about the same emulator, but check the suggested solution and try to do the same for the emulator you are using:
https://forum.recalbox.com/topic/25156/multi-disk-sur-sharp-x1-et-atari-800/9