Arm9loaderhax coupled with AuReiNand gives us lucky 3DS users the amazing option of running Custom Firmware on sysnand. The advantages of this are as follows:

• Much faster and more reliable CFW cold booting compared to menuhax + emunand
• Slightly faster CFW cold booting compared to arm9loaderhax + emunand
• Using 2GB of SD card space for emunand is no longer needed (but still recommended to keep a 9.2 emunand around)
• GBA ROMs only need to be installed once, since they run from sysnand now!

Most CFW users will already have a 9.2 sysnand which is usually kept as vanilla as possible, and then an emunand running a higher FW version (i.e. 10.5) booted through CFW. With arm9loaderhax and AuReiNand, we can now swap the firmware versions over so 10.5 runs directly on SysNand, and EmuNand is used only when 9.2 is really needed (e.g. for running decrypt9). This tutorial will walk you through the process of swapping your sysnand and emunand, and changing your arm9loaderhax to use AuReiNand in order to cold boot directly to a patched 10.5 sysnand.

This tutorial assumes the following:

• You have a 9.2 or below sysnand and CFW running an emunand of a higher firmware version
• You know how to verify a SysNAND backup using md5
• You know how to back up your sysnand, emunand and SD card
• You know how to access hax to get to the Homebrew Launcher
• You know how to install homebrew apps on your 3DS
• You know how to install CIAs
• You have already captured your OTP and built an arm9loaderhax installer
• You have FBI installed on your sysnand

I won’t explain how to do all of these as this guide is intended to be an overview of the process I used to swap my sysnand and emunand.


If you follow this guide and do not have a valid sysnand backup, you risk bricking your console and this may not be recoverable without a hardmod.

This guide involves updating your sysnand to 10.5. If you don’t have a reliable way of downgrading to 9.2 if you need to, don’t follow this guide. This means you need to be able to use arm9loaderhax to boot CFW, or have a hardmod and a NAND backup, if you want to undo this.

Do not attempt this procedure without a working arm9loaderhax installer. A hardmod is not required but is recommended.


You will need:

• Homebrew hax already set up and running on your sysnand
• CFW already installed with a working emunand
• Decrypt9
• EmuNAND9
• MiniPasta
  
• AuReiNand mod (do not install this yet)

If you already have arm9loaderhax set up to boot your emunand, you will need to remove it. This is because one of the needed tools, decrypt9, can only run from sysnand. Arm9loaderhax will prevent you from entering sysnand at all, so will need to be removed. I did this by restoring a vanilla 9.2 sysnand backup which I took from the console prior to installing arm9loaderhax.


Stage 0: Make a backup of your SysNand, EmuNand and 3DS SD card

Seriously, you’ll be glad you did if something goes wrong. This process involves a lot of messing around with both sysnand and emunand.


Stage 1: Dump EmuNAND partitions

1. Boot your 3DS to sysnand
2. Launch hax and run MiniPasta
3. When back at sysnand, launch hax and run Decrypt9
4. Go to “EmuNAND Options” and then “Partition Dump”
5. Dump each of the partitions with the exception of FIRM0 and FIRM1, pressing B after each one to return to the menu and dump the next partition
6. Press START to quit Decrypt9, and reboot back to sysnand

Stage 2: Downgrade EmuNand to 9.2

1. From sysnand, launch hax and run MiniPasta
2. When back at sysnand, launch hax and run EmuNAND9
3. Choose “EmuNAND Manager Options” and then choose “Clone SysNAND to EmuNAND”
4. Once this is complete, press START to reboot
5. From sysnand, launch hax and run TinyFormat to format SysNand and unlink NANDs
6. Once the system reboots, complete the initial setup without linking NNID
7. Once you are at the home menu, set your sysnand theme to red
8. Launch hax and run CFW to get into emunand
9. Once in emunand, set the theme to blue
10. Power off the 3DS

At this point, your sysnand and emunand should both be on 9.2, and you should have dumps of your original emunand. The purpose of setting the NAND colours to red and blue is to ensure you can tell which NAND you are in, since they are both at this stage running the same FW version and will look identical.


Stage 3: Update SysNand to AuReiNand CFW 10.5

1. Take out your 3DS SD card and put it in your computer
2. Replace the rei folder, arm9loaderhax.bin and ReiNand.dat in the root of your SD card with the ones from AuReiNand.
3. In the new rei folder on your SD card, place the firmware.bin and firmware90.bin from the FIRMs archive linked from the AuReiNand GitHib page
4. Create an empty file on the SD card in the /rei folder called updatedsysnand
5. Put your SD card back in your 3DS and boot it up to sysnand
6. Launch hax and run arm9loaderhax.3dsx to install the loader
7. If you get stuck on a message saying “Exploiting arm9…”, you can safely reboot your 3DS
8. The 3DS will reboot once this process is complete
9. You should now be in sysnand but running ReiNand. Verify that arm9loaderhax has been installed by powering off your 3DS, removing the SD card and powering on again. Your system should hang on a black screen because the arm9payload is not available. If your 3DS boots to sysnand without the SD card inserted, this means that arm9loaderhax has not been installed properly and you MUST NOT proceed
10. Once you have verified that arm9loaderhax is working, replace the SD card and power on your 3DS to boot to sysnand
11. Open System Settings set up your Internet connection
12. Update to 10.5 (seriously, don’t do it unless you’re certain the CFW is running by doing the SD card removal test in step 9. If you update to 10.5 without CFW up and running, you risk not being able to run any unsigned code, meaning you could end up stuck on 10.5 with no CFW)
13. Once the update is complete and the system has rebooted, enter System Settings to verify that you are now on 10.5

Step 4: Reinject emunand partitions to sysnand

This stage will make your new 10.5 sysnand how your emunand used to be

1. Power off the 3DS
2. While holding L, power the 3DS back on. This will boot into the 9.2 emunand
3. Launch hax, and run Decrypt9
4. Choose “SysNAND Options” and then “Partition Inject”
5. Inject each of the partitions in turn, with the exception of FIRM0 and FIRM1, pressing B after each one to return to the menu and inject the next partition
6. Press START to quit Decrypt9 and reboot back to SysNand.

If everything went according to plan, you should be looking at your sysnand but with all your CIAs showing. In my case, they were all back in presents and out of their folders which was a mild inconvenience. I also lost my custom theme, so that had to be reinstalled.


Final checks

1. Launch a CIA from sysnand to verify that it works. Successful launching of a CIA will indicate that the sysnand CFW is working
2. Enter System Settings from sysnand to confirm that you are on 10.5
3. Power off your 3DS, and power it back on while holding L. You should then be booted to your emunand, which will resemble your sysnand before the swap over
4. Enter System Settings from emunand to confirm that it is on 9.2
5. Now, do another sysnand, emunand and SD backup!

 

[democracy]

I've just swapped the NANDs this way, works great! And so simple! Don't forget to create the blank rei/updatedsysnand file and to delete your NAND backup files afterwards!

Now trying to decide if I even need to keep a 9.2 EmuNAND around anymore,

You need it if you want to ever update arm9. Do you have an old 3ds?

 

[dark_samus3]

You need it if you want to ever update arm9. Do you have an old 3ds?

Nah, recovery mode will be able to take care of this stuff once we get it done

 

[sj33]

You need it if you want to ever update arm9. Do you have an old 3ds?

arm9loaderhax is installed on my Old 3DS, but I also have a New 3DS with Gateway. My thinking is that I could just use my New 3DS for tasks I cannot do on my Old 3DS.

That said, it sounds like it might be best to wait until recovery mode is fully finished.

 

[caytung07]

Now I only have Arm9loader with 10.6 sysnand with FBI running fine, don't have emunand anymore, hold X but no Decrypt9, Am I stuck and never go back?
And I've patch AGB on sysnand 10.6 but cant play GBA VC, just black screen, any help?

 

[Tomsquik Chill]

@mashers I feel like this is the really complicated way to do it.... here's the simple way

• boot Decrypt9 however you want, even directly from a9lh if you're using the latest release
• Go to emuNAND options and dump CTRNAND
• Go to sysNAND options and dump CTRNAND (make sure not to overwrite the emuNAND CTRNAND)
• flash the emuNAND CTRNAND into sysNAND
• flash the sysNAND CTRNAND into emuNAND
• ???
• Profit

This has been tested and was one of the first ways it was done by @Shadowtrance

Is it work with n3ds jpn region change to eng on emunand? my sysnand still jpn 9.1
Thanks

 

[sj33]

Now I only have Arm9loader with 10.6 sysnand with FBI running fine, don't have emunand anymore, hold X but no Decrypt9, Am I stuck and never go back?
And I've patch AGB on sysnand 10.6 but cant play GBA VC, just black screen, any help?

Install AuReiNAND 3.8, then rename Decrypt9.bin to arm9payload.bin and put it in the /Rei directory. Then hold L+R on startup to boot Decrypt9.

 

[caytung07]

Install AuReiNAND 3.8, then rename Decrypt9.bin to arm9payload.bin and put it in the /Rei directory. Then hold L+R on startup to boot Decrypt9.

Thanks, I changed two file: arm9bootloader.bin and arm9loaderhax.bin of an older BootCtr9 version then ARM9LH can load decrypt9wip.bin in a9lh folder properly
About GBA black screen on CakeFW 10.6 with patched AGB, any suggestion plz!

 

[Housey]

@mashers I feel like this is the really complicated way to do it.... here's the simple way

• boot Decrypt9 however you want, even directly from a9lh if you're using the latest release
• Go to emuNAND options and dump CTRNAND
• Go to sysNAND options and dump CTRNAND (make sure not to overwrite the emuNAND CTRNAND)
• flash the emuNAND CTRNAND into sysNAND
• flash the sysNAND CTRNAND into emuNAND
• ???
• Profit

This has been tested and was one of the first ways it was done by @Shadowtrance

Does this swap over your NNID and stuff? I'm curious because some of that info is kept in nnidsave.bin and other partitions. I just want to be sure.

 

[dark_samus3]

Does this swap over your NNID and stuff? I'm curious because some of that info is kept in nnidsave.bin and other partitions. I just want to be sure.

Yep, most if it is kept on the SD card

 

[SomeGamer]

What will happen if I do a System Format on AuReiNand sysNAND with A9LH installed?

 

[Housey]

Yep, most if it is kept on the SD card

Thank you, it worked perfectly.

 

[davhuit]

Isn't region change easier/faster if you have an harmod?

I have a hardmod and already tested/confirmed a while ago I could inject a proper emunand to replace sysnand so I guess if I want to get swap my old 3DS from japanese to european, I could just change the region of emunand, then backup this region-changed emunand and inject it over sysnand?

Or maybe it won't just work that way because of some incompatibility with the region change?

Edit : I can confirm it. Managed to convert my japanese emunand to french, then restored the emunand backup on my sysnand and it worked fine. I then tried an official firmware update (10.6) to check if everything was okay and it updated fine.

So now, my japanese O3DS have an european sysnand (but I also kept the japanese nand backup just in case I want to switch again).

 

[FenrirWolf]

What will happen if I do a System Format on AuReiNand sysNAND with A9LH installed?

System formats don't do anything to the firmware, so all you would have is a formatted a9lh system.

 

[Housey]

System formats don't do anything to the firmware, so all you would have is a formatted a9lh system.

system format would wipe the SD card too so you'd need to put your cfw files again otherwise it won't boot

 

[FenrirWolf]

system format would wipe the SD card too so you'd need to put your cfw files again otherwise it won't boot

Right, there is that part to watch out for. Using TinyFormat might be preferable for that reason.

 

[Balerion]

Not totally correct with recent developments. (still work in progress)

Sooo does this work with n3dsxl? I was able to backup both partitions just fine through hbloader but i'm skeptical to do the restore process

Edit: nvr mind. Im an idiot

 

[Incolbum]

When I try booting arm9loaderhax, this happens.

Any reason for this? my sysnand was flashed into my emunand, so they're both the same. 9.2.0-21E.

Also, if I were to flash a region-changed emunand over my sysnand after doing this, would that work?

EDIT: Btw, using cakes.

 

[TreyTrent]

system format would wipe the SD card too so you'd need to put your cfw files again otherwise it won't boot

Are you sure about that? I don't remember my 3DS wiping the card. The 3DS side stuff yes, but not the cards data outside what the 3DS used.

 

[Housey]

Are you sure about that? I don't remember my 3DS wiping the card. The 3DS side stuff yes, but not the cards data outside what the 3DS used.

I'm not! I haven't used system format myself, I've only heard people suggest to system format with the sd card out.

 

[dark_samus3]

When I try booting arm9loaderhax, this happens.

Any reason for this? my sysnand was flashed into my emunand, so they're both the same. 9.2.0-21E.

Also, if I were to flash a region-changed emunand over my sysnand after doing this, would that work?

EDIT: Btw, using cakes.

You need to use a 9.0 firm