sudomod

I'm trying to configure a gameboy cartridge that acts as an SD card reader (like wermy originaly did) but all i keep getting is error messages on boot up. I tested for continuity so everything should work. What could be the problem?

P. S. Yes I'm doing it don't try to talk me out of it, I have my reasons .

Hi.
Probably is best you upload some pictures of the wiring.
Maybe lack of filtering? Thick wires?
But as i said, pictures would help...

Try making the wires as short as possible. You may also need to add decoupling capacitor between the power and gnd.

I tried with the capacitor before, didn't really change a thing.

Now I tried shortening the wires between the reader and the PI but at this moment all I get is the rainbow screen.

How about a different sdcard with new installation?

The instalation is fine. I tested it on another RPi zero.

This does not help you, just my experience:
I did this MOD as well and the bootup worked sometimes. This prooves the right wiring and function in general.

I discharged this MOD finally because I did not saw anymore possible improvements in my wiring.
In addition I wanted to overclock the SD card later on to 100MHz which would never work with this laggy MOD.

This MOD is quite laggy at all, maybe try another SD Card.

Still working at it. What kind of wire do you guys use for this? Is it OK to use thiner wire like the ones in USB cables or is it better to use a thicker wire?

Thinner should be fine since there is no power consumption from sd card. I guess any fault is caused by interferience. Maybe shild in any means could help and of course wires as short as possible. And a stable power supply. This is the reason for the capapcitor betwenn power and ground very close to the sd card.