Hacking Hardware Homebrew My Friend's Bricked Up 3ds

[ImBrickedUpLikeA3ds]

My friend gave me his bricked 3DS, and I was wondering how I could fix it, or if it's possible.

According to him, he was interested in using Extended Memory Mode games on his Old 3ds. It's Japanese (3ds LL,) and he region changed it to English (America, I assume.) He read something, saying that it may struggle to run those games and that mode on a region changed system, and that it's recommended you system format. So, he went to format the system (I'm not sure how exactly) and it gave him a message saying that it would delete everything on his SD card.
After this, he powered off the system and removed his SD card, because he didn't want to lose all the files. He put the SD card in his computer, but it wasn't able to be read. He decided to format the SD card. He wasn't able to backup the files that were previously on the SD card, so they got deleted with the formatting.

Then, he put the newly formatted SD card into his 3DS and powered it on. And... the screens were black, and the blue light stayed on.

He tried the directional buttons to try to access the recovery mode, to get to GodMode9, etc. Nothing, still blank screens.

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There are some things that I've tried, but I'm at a loss, and wanted any possible suggestions.

-Copied my hacked New3ds files to the SD card.
-Used the most updated files I could find to replace my old New3ds' files. (since I hadn't updated mine in years, and he recently hacked his Old 3ds a month ago.)
-Turned on the Old 3ds without SD card
-Tried to access recovery mode with the New3ds files on his Old 3ds.

If it some how helps in any way, he says he used these two videos to help hack his Old 3ds, and region change it.
For region change:
For homebrew/hack:

Any advice is appreciated, and if this isn't enough detail, I'm sure I can provide more.

 

[Kwyjor]

Never follow video guides. They tend to be out of date, incomplete, and/or inaccurate. (Also, one of the ones you posted is already coming up as "This video is unavailable" for me.)

The first thing I would suggest is to try using data recovery tools on the SD card. It's not necessarily too late if you want to recover the save data. Testdisk or Easeus are often recommended. If you don't care about any of the old data on the SD card, then never mind.

Regardless, at this point you should probably get a new SD card, since if the current one already had problems once, it might have problems again – and new SD cards are cheap enough anyway. Make sure you test the new SD card with h2testw before you start using it, and of course make sure it is properly formatted. All you need to set it up is https://3ds.guide/restoring-updating-cfw .