Broken 3ds with blue light and black screens, possible CFW

[dewyD202]

let me start by saying that this is all new to me. i bought a broken 3ds Xl (old version), to surprise my wife with for Christmas (as in 5 days from now). i knew when buying it that the blue light would turn on when powering up, but the screens wouldn't do anything. no color, no sound, nothing. i did some research and it looked like it would be an easy fix. i do have an electrical background so i wasn't worried about ribbon cable and messing with the electronics portion.

at this point, i have checked all the ribbon cables, replaced the bottom screen, replaced the Wifi card, i've done the system reset with A-Up-L-R, and nothing has changed. i am starting to think this had some CFW on it beforehand and the previous owner bricked it and couldn't get it to come back. the green wire to the wifi card was detached when i opened it, leading me to believe that they tried messing around with it thinking it was something else.

this did not come with a SD card and i can't get anything to pop up if i hold start and hit power or any other tricks i've seen online. how can i go about uploading new CFW when i don't know what was done before and don't personally know how to upload CFW in the first place?

i know im in over my head here and im looking for help at all, thank you!

 

[KleinesSinchen]

The problem with these kinds of error is that it can have multiple reasons – hardware and software side. Not knowing which is the case, you could easily spent a lot of time trying to solve a problem that doesn't exist while ignoring another one.
Given the hardware side is okay, this is the way to go:
https://3ds.hacks.guide/ntrboot

Ntrboot will allow starting no matter what is wrong with the software. I would not recommend soldering/hardmod. That can theoretically also be used to install B9S, but it requires knowledge about the currently installed official firmware version (known plaintext attack). Even if skilled in hardware tinkering, hardmodding carries a lot of risks and can do less than ntrboot (which will even work when the NAND is completely overwritten).

From software perspective, the behavior you described will show up when CFW has been uninstalled after modifying vital components or performing certain actions such as injecting a different friend code seed to unban a console… or a region change had been performed.