Homebrew Black Screen when hardmod SD Card is plugged in

[MamamamaOtototo]

Hiya,

I have a New 3DS XL, and I have already soldered the wires to it. I put a connector in the back of the case for an SD card adapter that I can plug into my computer, as is recommended by the guide. When I plug the SD card into the computer and turn on the 3DS, it shows only a black screen (forever) with a blue LED. I have to hold the power down for like 10 seconds to turn it off; disconnecting the SD card does not help. However, when the SD card is not plugged in and I start the 3DS, it boots just fine.

I guess my goal right now is to get the blue error screen so I can read the img. I am not using a recommended card reader. I will buy one if it'll solve the problem, but that's why I'm asking here first to see if this is normal behavior for unsupported SD card readers, or if my wiring is wrong. I did check everything with a multimeter and it seems okay, but I'll double check.

Thanks for the help.

 

[Kubas_inko]

are you sure your wires are correctly soldered (because you might have solder them badly, wrongly, you switched some wires i the connector)
Are you 100/ sure, it goes like this (also don't forget to plug sd card into reader first, then power on 3DS, then plug it in):

 

[MamamamaOtototo]

I took it all apart again today and re-soldered everything, shortened the wire lengths, and moved the GND connection to the capacitor in the picture instead of its original location (the game cartridge). Checked everything with a multimeter and I get perfect continuity between the SD card pads and the locations on the motherboard, with no short circuits. Same result though, black screen and blue LED. I'm gonna go ahead and try some other SD card slots, and then if those don't work, I'll buy the one on Amazon. I'm confident that the wiring is perfect.

Thank you for your help!

Success! I tried a few other card readers, and finally one of them worked! The DS turned on with a blue error screen. So, if anyone else has this problem, try another card reader!