Recently, some had problems with brand new cards that had a very little first partition concealed from most OSes for whatever reason, and formating from context menu in windows didn't solve that. I don't think that's the case here, if other games work. Are you sure of your dump? Dumping discs on yo...

I'm almost certain I bought one of the known-working SD cards, but perhaps reformatting it or trying another one would be worth a shot.

This is an isolated case. Alright then. Any ideas on what the source of the problem is? I was able to get a number of other games working just fine, namely Smash Melee and Mario Party 4, so I'm sure it can't be the SD2SP2 itself. But if it was the ISO files I feel like nkit tools would have told me...

I made a note about this by editing the Swiss compatibility list on the Wiki, but I figured out this forum exists and I probably should have posted here first to ask questions. As the title suggests, I couldn't figure out how to get Twin Snakes to work for the life of me and I've had this SD2SP2 set...

Apache Thunder wrote: Is this port accessible at all from homebrew software? If not then I suppose booting/accessing anything from this port would be impossible.

Actually, yes there has been some homebrew alternatives to the Gameboy player software called GBI. Other homebrew should be able to access it.