Some roms cause retroarch to return to the HBC when loaded. Specifically, marvel vs capcom and SFA3. I have loaded a rom as large as 23 mb so I don’t think it’s a memory issue. These roms are listed as working in the compatibility list posted here. Any suggestions?
Edit: SFA3 loads. MVSC and Xmcota do not. Works on Mac OS X.
I remember with X-Men CotA it requires the parent rom and child rom to work for some reason. I can check the exact filename when I get home from work this evening.
Can you clarify parent / child roms? (Newb alert)
Here’s what I have. The parent ROM is the larger file containing the main game data, the child ROM is the smaller file containing often country or region specific data, for example, the Asia version or US version of a game. To play a child ROM, the parent ROM must be present in the same folder as the child ROM requires the files from the parent ROM to function. If you have the two ROMs as shown in my image, X-Men Children of the Atom should work.
Thanks for that. Turns out the issue is that I should be loading final burn alpha roms rather than (what I assume was) mame roms. Weird because some worked when loading the CPS2 core and others didn’t
Glad it’s working anyway!
The compat list I posted is for 1.0.0.2 and I noted that. The FBA cores are bigger now in 1.2x because of extra features in the RA side and this reduces available RAM.
If you can get stuff on the 1.0.0.2 list to work in 1.2.2, great. But there is an element of luck with that with the bigger ones … the memory squeeze effect has pushed some out, so there is more trial and error testing needed which is exacerbated by some other bugs.
Also know that zip size is not the same as pure ROM code size.
And yes you need to be drawing from an FBA romset instead of MAME one.
The actual rom dumps take from the arcade boards themselves are mostly all the same code, and the majority of romsets between FBA and MAME share common file archives and contents.
But subtle file naming differences of eprom blocks within the zip archives can be different in some games rom versions, and also the expected zip archive name.
It seems to be more prevalent with the Capcom CPS boards, probably due to decryption progress in recent years and multiple dump efforts.
I don’t have exact examples right now of eprom names but they could be like A26.001 in a MAME rom and 001.A26 in an FBA one.
Another example is the rom archive name - example Taito’s “Rainbow Islands”. In one romset it might be required as rbisland.zip and in another it might be rainbow.zip.
Sometimes the difference is just the zip name. Other times it’s the files inside the zip that the emulator expects. And other times again it’s both the zip name and different named contents.
Unfortunately it seems with RA on Wii/GC, if something goes wrong at the rom open/read phase it will crash the whole thing rather than throw back an error.
This makes testing extremely laborious, especially for GC. Which is why the list was done in the first place… save someone elses time from being wasted 
It might be worth adding an md5 checksum for each rom in the compat list and that would be a simple enough thing to batch process.