Welcome!

Very good, I was able to get it to work however I didn't quite understand some things:

1. On some occasions it sends me to the cross hatch test menu and on other occasions it sends me to the game.
2. If the rom loading failed due to some error in the data, I could no longer call the option but instead had to forcefully close the program and start again.
3. I managed to play kof games, but necessarily in DrvName I had to leave mslug instead of kof98, 99, etc.
4. Despite trying to associate the rom with a parent so as not to repeat the unmodified roms, I did not understand how to do it, I had to leave a *.zip with all the roms, the modified ones and those of the unmodified parent game.

Perfect, I try with a patch of kof99 dreamcast version and svc playstation version.

Well, it would be good if he explained what the *.dat syntax is or what data goes there and in what order. I don't think the syntax is the same as the kawaks loader data, but the idea should be similar.

fbneo's romdata allows some romsets that are not on the list, but run with a common driver.

The format of *.dat is as follows:
///////////////////////////////////////////////////////////
// ZipName:  Zip names that are not in the game list     //
// DrvName:  Select which driver exists in the game list //
// ExtraRom: NeoGeo specific extra rom                   //
// FullName: Detailed name of the game                   //
///////////////////////////////////////////////////////////

ZipName:  cyborgforce
DrvName:  mslug
ExtraRom:
FullName: "Cyborg Force! (Homebrew)"

// romname romsize crc type
cyborg-p1.bin 0x0100000, 0x89e1c728, 1 | BRF_ESS | BRF_PRG
cyborg-p2.bin 0x0300000, 0xe4a8b27a, 1 | BRF_ESS | BRF_PRG
cyborg-s1.bin 0x0020000, 0x5bd29810, 2 | BRF_GRA
cyborg-c1.bin 0x1000000, 0x77078687, 3 | BRF_GRA
cyborg-c2.bin 0x1000000, 0xa5abdb83, 3 | BRF_GRA
cyborg-m1.bin 0x0010000, 0x06da3cec, 4 | BRF_ESS | BRF_PRG
cyborg-v1.bin 0x0800000, 0xdc50718c, 5 | BRF_SND
cyborg-v2.bin 0x0800000, 0x8135d5a8, 5 | BRF_SND

Cyborg Force! (Homebrew) as an example:

ZipName, the set we want to use, usually *.zip or *.7z.

DrvName, the driver we want to run from, it is recommended to use clone when possible, so that we don't have to prepare some ROMs that are common to the parent set;

FullName, well understood, the name of the game.

romname/romsize/crc/type，It's almost identical to the fbneo source code, and corresponds to the ROMs in our ZipName zip file, just write to *.dat.

The dat file can be saved anywhere we can find it, and romset can just be saved in one of the paths of the 20 recognizable ROMs.

After that, Ctrl+R, find dat and select it.

By the way, a graphical listing of romdata functions will be coming next to make it easier to use.

I see the Japanese version: Kaettekita Mario Brothers (Japan), there is also an English patch for this game.

https://www.romhacking.net/translations/6364/

Thanks for the tip! The related support will be added to the next NES/FDS update!

Hi Xerf84,
I don't have a full understanding of this feature, but from what I understand so far, it allows one to side-load romsets that fbneo doesn't have yet in it's database.  Maybe taoenwen will explain better, as he added it

best regards,
- dink