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!

 

[Svaethier]

After swapping the NANDs, can I completely remove the emuNAND from my SD Card?

I wouldn't do it just incase you ever need it in the future (people are using theirs to test stuff right now).

 

[PedroPVJ]

Keep emuNAND as a safe mode

 

[dkabot]

After swapping the NANDs, can I completely remove the emuNAND from my SD Card?

Theoretically, but not recommended. At the moment, the only way to run Decrypt9 in this setup (barring a downgrade of sysNAND) is to run it through 9.2 EmuNAND with 9.0 FIRM.
However, you could get a second, small SD card (4GB or something) and put your 9.2 EmuNAND there, then stow it away for safety.

 

[DigitalJosee]

I wouldn't do it just incase you ever need it in the future (people are using theirs to test stuff right now).

Theoretically, but not recommended. At the moment, the only way to run Decrypt9 in this setup (barring a downgrade of sysNAND) is to run it through 9.2 EmuNAND with 9.0 FIRM.
However, you could get a second, small SD card (4GB or something) and put your 9.2 EmuNAND there, then stow it away for safety.

It doesn't worth the risk, 1Gb isn't that much.
Will keep my emuNAND, better safe than sorry.

 

[Svaethier]

It doesn't worth the risk, 1Gb isn't that much.
Will keep my emuNAND, better safe than sorry.

yes exactly, not like you'll use it much anyways but nice to have around anyways

 

[dkabot]

It's very good to have around.
Over on the Decrypt9 thread I was told that if it loads on the 9.2 EmuNAND it'll work, so as long as you make post-A9LH backups it should work as a basic brick protection.
So long as you don't break FIRM0/1, you can always restore through EmuNAND Decrypt9. Bonus points if you do partition backups, since then the restore can't fail to write back FIRM0/1.

 

[Supster131]

It's very good to have around.
Over on the Decrypt9 thread I was told that if it loads on the 9.2 EmuNAND it'll work, so as long as you make post-A9LH backups it should work as a basic brick protection.
So long as you don't break FIRM0/1, you can always restore through EmuNAND Decrypt9. Bonus points if you do partition backups, since then the restore can't fail to write back FIRM0/1.

But if you create a sysNAND backup that already has A9LH, won't it stay when restoring it?

(I think Decrypt9 should add a new backup feature which backs everything up except FIRM0/1.)

 

[dkabot]

But if you create a sysNAND backup that already has A9LH, won't it stay when restoring it?

(I think Decrypt9 should add a new backup feature which backs everything up except FIRM0/1.)

It will stay when restoring it, just thinking (too) deep into it.
If the restore fails to write a partition, and that doesn't break the NAND entirely, then having backups that don't include the FIRMs means it can't break your boot.

That's just theoretical though, I don't actually know what'd happen if you killed the power while restoring.

 

[Svaethier]

But if you create a sysNAND backup that already has A9LH, won't it stay when restoring it?

(I think Decrypt9 should add a new backup feature which backs everything up except FIRM0/1.)

not sure but it probably would, I wouldn't try it though as I would just use a sysnand backup from before a9lh.

 

[Supster131]

not sure but it probably would, I wouldn't try it though as I would just use a sysnand backup from before a9lh.

Yeah, probably wouldn't be a bad idea if NAND backups that exclude FIRM0/1 can exist then. (Since doing them manually one by one can be a hassle.)

 

[Svaethier]

Yeah, probably wouldn't be a bad idea if NAND backups that exclude FIRM0/1 can exist then. (Since doing them manually one by one can be a hassle.)

and the fact restoring a back up nand with the FIRMs in place can probably brick it or render emunand no longer usable.

 

[dkabot]

Yeah, probably wouldn't be a bad idea if NAND backups that exclude FIRM0/1 can exist then. (Since doing them manually one by one can be a hassle.)

To be fair, FIRM isn't too big. I don't think it'd matter if the backup had it, and some things might be confused if it didn't.
A "restore without FIRM" option, however, would be pretty sweet.

 

[Supster131]

and the fact restoring a back up nand with the FIRMs in place can probably brick it or render emunand no longer usable.

To be fair, FIRM isn't too big. I don't think it'd matter if the backup had it, and some things might be confused if it didn't.
A "restore without FIRM" option, however, would be pretty sweet.

Both of you just stated different things in terms of the FIRM.

 

[Svaethier]

To be fair, FIRM isn't too big. I don't think it'd matter if the backup had it, and some things might be confused if it didn't.
A "restore without FIRM" option, however, would be pretty sweet.

well you can downgrade sysnand with the 9.2 firmware cia files including NATIVE_FIRM in place which I'm sure writes to the FIRMs and a9lh still works so maybe this theory has exploded?

 

[dkabot]

Both of you just stated different things in terms of the FIRM.

I would say we stated similar things. Could be wrong.
They said restoring one with FIRM could brick or render EmuNAND unusable (I presume they mean restoring to SysNAND).
I said it'd be nice to keep it in the backup, for compatibility, but just have an option to not use it in restoration.

well you can downgrade sysnand with the 9.2 firmware cia files including NATIVE_FIRM in place which I'm sure writes to the FIRMs and a9lh still works so maybe this theory has exploded?

I've heard the opposite, that the patch only stops what official updating does, but not what SysUpdater does.

 

[dpad_5678]

Isn't having EmuNAND better so you don't have to screw with sysnand?

 

[Svaethier]

I would say we stated similar things. Could be wrong.
They said restoring one with FIRM could brick or render EmuNAND unusable (I presume they mean restoring to SysNAND).
I said it'd be nice to keep it in the backup, for compatibility, but just have an option to not use it in restoration.


I've heard the opposite, that the patch only stops what official updating does, but not what SysUpdater does.

well I'm living proof that downgrading with sysupdater on sysnand with a9lh in place does indeed work

 

[dkabot]

well I'm living proof that downgrading with sysupdater on sysnand with a9lh in place does indeed work

Which confuses me greatly.
Personally, not going to try it. All word I got says Decrypt9 works through EmuNAND and that's all I need 9.2 for.

 

[Svaethier]

Which confuses me greatly.
Personally, not going to try it. All word I got says Decrypt9 works through EmuNAND and that's all I need 9.2 for.

just goes to prove that what people say can be wrong sometimes I downgraded my sysnand from 10.5 to 9.2 two days ago and not a thing went wrong.

 

[dkabot]

just goes to prove that what people say can be wrong sometimes I downgraded my sysnand from 10.5 to 9.2 two days ago and not a thing went wrong.

Mind if I ask why you did so?
Just not seeing a reason to, aside from being a who lives life following their own rules (which I don't object to)