I apologise that this is an old thread but it sounds similar to what I am having at the moment.
I have been trying for months now to try fix my JAP N3DS LL.
I cant remember exactly what exploits I used because it was over 4 years ago, I downgraded my JAP N3DS LL to 9.x firmware.
Then I set up an exploit that allowed you to set a button combination to run the exploit when powering the console on.
I set this to DPAD DOWN when powering the console on. If nothing is pressed when powering the console on, it would boot like a normal 3DS console would.
I used this exploit which then booted into HBL, from there I would boot into GateWay.
This exploit would also allow me to boot other apps from the HBL menu such as FreeShop (which was dead) and Luma CFW, but I would only boot into GateWay mode to use my GateWay flash card and use its Cheat Code finder tool that is included with GateWay.
Everything had been working flawlessly for ages, then I had cancer so I had stopped gaming completely for almost 2 years.
Then when I came back to my 3DS, having already forgotten what exploits I had already set up, but I remembered how to boot my 3DS console into GateWay.
Then this is where I think I may have caused my problem.
When I let my son use my 3DS console, he kept trying to open these other applications that came as default on my JAP 3DS consoles home screen.
I assumed these were some sort of demo applications for games or some form of application. I had no idea because all text is in Japanese, but they looked like game demos as one was something relating to Pokémon.
So to stop my son from keep trying to open these applications that constantly shown on my 3DS home screen. I had FBI Installer installed to my 3DS console.
I used to primarily to create a NAND backup of my 3DS console.
But one day I thought it would be possible to use FBI Installer to remove these demo applications off my 3DS console so that these tiles will no longer show on my 3DS home screen, thus putting a stop to my son from trying to run them.
I think when I did this that I might have deleted something by mistake, something system related. Because before I did this, the 3DS console worked perfectly fine.
I assume its semi bricked because when I try turn it on, nothing happens at all, with or without an SD card.
Even if I try holding the DPAD DOWN button, which the exploit was set to trigger when powering the console on. Nothing happens at all.
The 3DS console however is able to go into the consoles Factory Reset menu when powering the console on.
The Factory Reset where it takes you to a screen where you can connect to your WiFi and download/install the latest firmware from Nintendo.
I have another 3DS console which is Australian, this also used to be set up the same, but it was the MRS console and she had forgotten what button was set to boot the exploit, anyways, this console I then installed Luma CFW on it (not touched it since, so no clue what version it is).
But I used this 3DS console and booted it into the same Factory Reset screen as my JAP 3DS, so that I can cross check what the on screen menu buttons are saying.
So I was able to configure my JAP 3DS console to my WiFi and saved the settings.
The JAP 3DS console would then perform a Network Test to make sure it has a WiFi connection.
You can see on the top screen that it is able to connect to my router, you see it getting a connection, then it ALWAYS FAILS on the last part where it tests if it is actually receiving an Internet connection.
So this is as far as I can get on my JAP 3DS, I have no idea why it won't get an active connection from my WiFi to then let the consoles Factory Reset to download/install the latest firmware from Nintendo.
At first I assumed maybe its because it is a JAP 3DS console and I am in the UK. Maybe Nintendo servers reject it connecting.
Then I also assume maybe its possible that though the JAP 3DS console didn't have an actual CFW permanently installed, maybe they could tell that it had been used to boot GateWay.
But worse case is, I think when I was uninstalling these JAP demos off my 3DS home screen, I think I probably uninstalled something system related that is required.
Everything was working perfectly fine until I did this and I am absolutely pissed off with myself for fucking about trying to remove these JAP demo icons from my 3DS home screen.
I have tried all sorts, I have multiple SD cards that I have formatted to try set the SD card up for other exploits.
Me hoping, wishing that there is some form of exploit out there that I can simply put onto an SD card and like my old exploit, it can trigger the exploit before the actual 3DS console tries to boot its default firmware.
And I am wondering if such a thing exists, if so, what is it please so I can read up about it and get it set up on an SD card.
Hoping if it is able to trigger an exploit that one of its features be either let me re install my NAND backup so it is restored back to how it was before I fucked it up.
Or, allow it to install CFW permanently onto the console so that it instantly boots CFW everytime the console is turned on.
If I remember correctly my NAND backup is named something like:
System backup.bin
I hope someone can help me and I apologise for this very long message, but I am trying to give as much information as I can.
I really would love to get back to using GateWay 3DS so I can return to using its Cheat Code Finder and return to making 3DS cheat codes.
Thanks