This is thanks to u/perkel

After Many tries and hours I found this users steps and followed them to success (n3ds). I got through the downgrade process and it automatically rebooted without any problems (no black screen or having to remove the sd).

Here's Perkels solution, and I quote:

"- formated my n3ds (had 10.1, updated to 10.3 then format)
- formated SD (32gb kingstone class10) with SD formater (format overwrite + formatsize adjustements)
- downloaded 9.2-20E firmware for N3DS
- checked md5 of above firmware via this site
MD5: 6dcca8fcbc9a28c82c2a4e5182f3acf8
SHA-1: e7c77bf205137167f1f1befa0c4db9d879a21a2e?
- downloaded this systemupdater which julian posted (SULib one) MIRROR

thread where given (if curious):
https://gbatemp.net/attachments/sysupdater-zip.34449/

- downloaded starter kit for homebrew (from smealum site)
- installed TeraCopy to ensure nothing will be damaged via copy/paste on SD card

- put SD to pc
- copy everything lower via teracopy program! (it will show your option when you do it just via copy/paste like normally you do after you install that program)
- copy starter kit folder content to sd card
- copy sysupdater to 3ds folder in your SD card
- copy updates folder to your SD card once you unpacked your downloaded and checked via md5 sum FW
- get your SD card to your 3DS and set up your 3DS (date, time etc.)
- change your theme to something else and back to default (to ensure menuhax will work)
- do browserhax (scan QR code [L+R and then that left sticker] from this site)
- you should go into HomeBrew thanks to above
- choose menuhax manager and install menuhax
- restart your 3DS and hold L to go into homebrewlauncher directly

Once above is done you have properly installed homebrew on 10.3 and it is confirmed that all files are 100% safe to use (that FW you downloaded) and nothing weird should go wrong (it still has that chance though)

Once above was done i started sysupdater from homebrewlauncher.
Since memchunx doesn't work most of the time i had to try 7-10 times before i got #8 success and sysupdater menu.

Then i pressed Y, nothing happened for 3-5 seconds
Then cheking CIA files... or whatever that was for 10-30 seconds
Then it started to install CIA files
Then it got to autorestart in 10 seconds
Autorestarted (NO CRASH)
Booted into 9.2 system without problem perfectly (without taking out SD card)

In other words perfectly updated without single crash (aside from getting into sysupdate menu)

I give my humble thanks to whoever worked on memchunks, julian for this fantastic build and ton of other people that showed me way to ensure everything will work correctly (like teracopy, md5 etc).

Now i have 9.2 and i am wondering what should i do Good thing to wonder about "

Happy Downgrading!

 

[Chewiesaurus]

Thanks, I appreacitate the help.

Thanks to this version of sysupdater I managed to finally downgrade a N3DS XL EU and on the first attempt too (that worked I guess, sysupdater froze 5 times in a row before even loading the options). I tried several sysupdater variants and all I managed to do before was to soft brick it 3 times with hours of trying to innitialize the downgrade process.

 

[Lycan911]

I have some questions before attempting this:

1) Can Activity Log's data be backed up? It would suck if I lost it after the format.
2) Is TeraCopy required? I never had problems with files corrupting when transferring them.

 

[Shadowfied]

I have some questions before attempting this:

1) Can Activity Log's data be backed up? It would suck if I lost it after the format.
2) Is TeraCopy required? I never had problems with files corrupting when transferring them.

As far as I know, you can not go and back up Activity Log specifically, it is almost impossible that it would be lost though, that would only happen if you hard bricked (which wont happen unless you are stupid) and then you would lose everything anyway.
You do not need TeraCopy. I just threw the files over with the windows explorer without any issues. For both my O3DS and N3DSXL. I'd advice you to verify the MD5 of the zip you get though to be secure.

Edit: Also, which "Format" are you referring to? The downgrade process does not involve any formatting.

 

[Lycan911]

As far as I know, you can not go and back up Activity Log specifically, it is almost impossible that it would be lost though, that would only happen if you hard bricked (which wont happen unless you are stupid) and then you would lose everything anyway.
You do not need TeraCopy. I just threw the files over with the windows explorer without any issues. For both my O3DS and N3DSXL. I'd advice you to verify the MD5 of the zip you get though to be secure.

Edit: Also, which "Format" are you referring to? The downgrade process does not involve any formatting.

By backing up Activity Log, I mean backing up its save data, as in, my charts, step count, play time etc.
As for the formatting, it is LITERALLY the first step in the tutorial OP posted. Formatting the system.

 

[Shadowfied]

By backing up Activity Log, I mean backing up its save data, as in, my charts, step count, play time etc.
As for the formatting, it is LITERALLY the first step in the tutorial OP posted. Formatting the system.

Oh, sorry. You don't ned to format at all. That's just a "safety" step I guess, not that it's gonna help. I didn't format either of my systems and all was fine. Never semi-bricked or anything.
Pretty sure the Activity Log is stored in NAND, which means you can't access it. However, after downgrading and setting up your EmuNAND you'll have full access to your EmuNAND and then you can back everything up.

 

[Lycan911]

SUCCESS, I'M STILL SHAKING

 

[Shadowfied]

SUCCESS, I'M STILL SHAKING

CONGRATZ! Now before you do anything, get to the Gateway menu and DO A SYSNAND BACKUP!!

 

[Lycan911]

CONGRATZ! Now before you do anything, get to the Gateway menu and DO A SYSNAND BACKUP!!

How do I do that? I'm still scared of doing anything without a step-by-step tutorial xD

 

[Shadowfied]

How do I do that? I'm still scared of doing anything without a step-by-step tutorial xD

You need to go to http://go.gateway-3ds.com on your 3DS. Not sure if you need the Launcher file. Just try going there on your 3DS and see if you can access it. If you can, head over to Backup System Nand, then let it back up, then store it safely on your PC.
Edit: Okay yeah, you need the Launcher.dat file. Head over to the Gateway website, go to Downloads, download the latest beta package, find the Launcher.dat file, put it on the root of your SD card, then go back to your browser and head to the aforementioned URL again!

 

[Lycan911]

You need to go to http://go.gateway-3ds.com on your 3DS. Not sure if you need the Launcher file. Just try going there on your 3DS and see if you can access it. If you can, head over to Backup System Nand, then let it back up, then store it safely on your PC.
Edit: Okay yeah, you need the Launcher.dat file. Head over to the Gateway website, go to Downloads, download the latest beta package, find the Launcher.dat file, put it on the root of your SD card, then go back to your browser and head to the aforementioned URL again!

Ok, backing it up now. It needed the launcher.dat so i downloaded it. What can I do with this backup in the future?

 

[Shadowfied]

Ok, backing it up now. It needed the launcher.dat so i downloaded it. What can I do with this backup in the future?

In case you fuck something up, you can now always restore your sysNAND, assuming that you have not bricked the system so hard that you can't even access it software wise, but even then it can still get recovered by having someone install a hardware mod, which will let you use this previously backed up sysNAND file. You're most likely never gonna use it, but that doesn't mean you should not absolutely treasure it.
If you're not aware, "NAND" is the built in storage, the files that are not on your game cartridges or SD cards, certain data is written there, such as the Activity Log that you treasure. Modifying the NAND can be dangerous, therefore, instead of modifying your original, we use "EmuNANDS", which as the name implies, is an Emulated NAND. By setting up EmuNAND, about 1 gigabyte of your SD card will be turned into a "fake" NAND which you will be using instead. Doing this, you'll be completely safe to do whatever you want there, as you can always restore it and mess about, since you're not gonna be touching the sysNAND.

So what you should do now, is decide which CFW you're gonna use, if you have a Gateway cart, the easiest method is to just follow their manual and set that up. Otherwise I'd recommend rxTools. If you're on O3DS (2DS included), check here, or if you're on New 3DS, check here.

PM me if you have questions

 

[Lycan911]

In case you fuck something up, you can now always restore your sysNAND, assuming that you have not bricked the system so hard that you can't even access it software wise, but even then it can still get recovered by having someone install a hardware mod, which will let you use this previously backed up sysNAND file. You're most likely never gonna use it, but that doesn't mean you should not absolutely treasure it.
If you're not aware, "NAND" is the built in storage, the files that are not on your game cartridges or SD cards, certain data is written there, such as the Activity Log that you treasure. Modifying the NAND can be dangerous, therefore, instead of modifying your original, we use "EmuNANDS", which as the name implies, is an Emulated NAND. By setting up EmuNAND, about 1 gigabyte of your SD card will be turned into a "fake" NAND which you will be using instead. Doing this, you'll be completely safe to do whatever you want there, as you can always restore it and mess about, since you're not gonna be touching the sysNAND.

So what you should do now, is decide which CFW you're gonna use, if you have a Gateway cart, the easiest method is to just follow their manual and set that up. Otherwise I'd recommend rxTools. If you're on O3DS (2DS included), check here, or if you're on New 3DS, check here.

PM me if you have questions

Thanks a lot for your help! I'll work on creating emuNAND and installing CFW tomorrow, I'll let you know if I need any further assistance

 

[Shadowfied]

Thanks a lot for your help! I'll work on creating emuNAND and installing CFW tomorrow, I'll let you know if I need any further assistance

Alright! Sleep tight and good luck tomorrow = ]

Oh, also, just so you're aware, when you create your EmuNAND, it clones your SysNAND, so all your stuff will now be in EmuNAND, which is exactly what you want.

 

[Lycan911]

Alright! Sleep tight and good luck tomorrow = ]

Oh, also, just so you're aware, when you create your EmuNAND, it clones your SysNAND, so all your stuff will now be in EmuNAND, which is exactly what you want.

Got it!

Also, I noticed that the Gateway menu has an option for dumping cartridges. Does that mean I can convert those dumps to CIA and install them on emuNAND? It would be nice for traveling and stuff, no need to carry cartridges.

 

[Shadowfied]

Got it!

Also, I noticed that the Gateway menu has an option for dumping cartridges. Does that mean I can convert those dumps to CIA and install them on emuNAND? It would be nice for traveling and stuff, no need to carry cartridges.

Yeah, it will dump them to .3ds files though, which can only be booted with a Gateway or Sky3DS cart, however, when you have rxTools setup, you can convert those .3ds files to CIAs.

 

[Lycan911]

Yeah, it will dump them to .3ds files though, which can only be booted with a Gateway or Sky3DS cart, however, when you have rxTools setup, you can convert those .3ds files to CIAs.

Awesome, thanks!

 

[Deeptrap]

I dont get what im doing wrong

i have 2 2ds.
both downgraded from 10.3 to 9.2.
but after this i cant start the browserhack anymore.

on my ds i see only a small slidebar if i go to the website thru the QR code.

cleaering cookies or cache nothing helps.

i can start emunand i i go to the gateway page.

anyone ?

 

[Shadowfied]

I dont get what im doing wrong

i have 2 2ds.
both downgraded from 10.3 to 9.2.
but after this i cant start the browserhack anymore.

on my ds i see only a small slidebar if i go to the website thru the QR code.

cleaering cookies or cache nothing helps.

i can start emunand i i go to the gateway page.

anyone ?

Click the slider

 

[Deeptrap]

Click the slider

Cantbelieve it

Asked this on serveral topics, up and downgraded the devices both two times .
2 and a half houres later, i only had to click the slider btw it works

 

[Marx7]

I got a question. I wanted to transfer CIA files from my old 10.3 emunand to my New 3ds emunand. Is it possible I can downgrade the old emunand using this method?