SNESpi

[abrugsch]

Why would they do that... Just seems crazy to not make it reversible

[DieKatzchen]

My only guess is that it's to avoid having to have any sort of storage for settings. If I ever need to have a pi boot from usb, I'll just have it handoff from the sd card. Unless it's a zero. Those are cheap enough I don't feel bad making permanent changes to it.

[beardedviking]

I tried a test build for this where I wired the sd card adapter to the cartridge's board and the cartridge connector to the Pi as seen in the gameboy zero build. I tested and confirmed all connections with the cartridge plugged in but still the Pi wasn't able to boot from the sd card.

How did you wire it ? do you have a picture ? , already tried twisting/bundle the wires ?, that did the trick for me many times, straight wires no boot, twisted them up, boot like a dream.

Wait, what? Seriously? No I haven't tried that but I sure will now!

[144TECH]

Yeah, but be sure you twist the wires very dense and compact, and may sound weird but thinner wires would work great, or just the wires from an usb cable,but again, twist them really good and tight, first solder the 4 on one end, then twist, and solder the other side or make them the right length and twist ,and solder them into place.
I'm curious if it works for you too, if not i have few other tricks.
Also, a picture of your wiring will make things more clear to see for us.

Greets