Missing Cores?

Games worked fine a few days ago but now they won’t launch. I just get a black screen for a couple seconds then moved back to the games list.

Outlier is Pokémon Silver which I have been regularly playing. That boots fine. I suspected the issue is with the cores. Pokémon Silver has its core selected but there are no cores listed for the other games.

Selecting a core seems like the obvious solution, but there is no option to select one. Under Emulator Options and Per-Game Settings, it just says System Default ((none)) for core options. In case it’s worth mentioning, System Options just gives a black screen.

I’m on a TrimUI Brick Hammer with PakUI. SD card is not stock. How can I get core options listed for my games again?