JoJo's Bizarre Adventure: All-Star Battle [NPEB01922]

Huh, my post got removed for some reason, dunno why? Could still be useful info for somebody out there.
The short of it:
If your game is loading the DLC infinitely, first open the emulator but don't start the game (The game might in fact have to be running, I don't remember). Open task manager, go to details, right click the emulator in the list and click set affinity, uncheck everything except CPU 0, try to start the game, if you get past the loading DLC stage, go back into task manager and check everything in affinity again.

Or you could try the Github solution that was posted above.