NOTE: The original guide is completely outdated now. Just use Decrypt9's 'keep a9lh' option to flash emunand backups to sysnand and you're good to go.

But if you really want to use this guide as currently written for some reason, here it is I guess:

Spoiler

DISCLAIMER STUFF: Switching to sysnand isn't for everybody. It makes Virtual Console games easier to work with and it boots a little faster than emunand does, but if those things don't matter to you then you might be fine keeping everything on your emunand. Just be warned that switching everything to sysnand means you need to take more care when it comes to dealing with system updates and when performing NAND restores. Make sure you understand what features are available in your CFW of choice when it comes to preventing updates from overwriting a9lh. AuReiNand and CakesFW both support this feature so I recommend you use one of them if you aren't already.

And while the arm9loaderhax installer is pretty well tested at this point, there still is a possibility of the installer bricking your system even if you've successfully used it before. If you would prefer to follow a guide that does not require running the arm9loaderhax installer again, you might want to check out Part 5 of Plailect's arm9loaderhax guide which details an alternate and more up-to-date method of how to get your emunand swapped to sysnand.

If that didn't scare you off, then let's get right down to things.

WHAT YOU'LL NEED:
-The latest version of your custom firmware of choice. Chances are you're using AuReiNand or Cakes if you're reading this.
-Decrypt9. Everybody loves them some Decrypt9.
-arm9loaderhax.3dsx compiled with your OTP.

note about arm9loaderhax.3dsx: You might want to recompile your arm9loaderhax.3dsx if you don't already have the latest version of a9lh. Just make sure that you use your own OTP file if you download the a9lh source again and it includes a dummy file. Some people have been caught off guard by that before. Alternatively you could simply use your current arm9loaderhax.3dsx and then use the newer SafeA9LHInstaller to update your setup afterwards.

You also might want to do a bit of housekeeping before performing the swap. Do you still have Menuhax hanging around on either of your NANDs, for example? Uninstall it. It will just confuse you later on.

HOW TO GET SWAPPIN':
1) Boot Decrypt9 and back up your sysnand to sysNAND.bin and your emunand to emuNAND.bin

If you're using AuReiNand, you'll need to hold L when booting the console to start your 3DS using firmware90.bin. That way Decrypt9 won't give you a red screen glare of displeasure when you try to run it.

2) Unmount the card in Decrypt9 and open it on your computer. Rename emuNAND.bin to NAND.bin, then rename sysNAND.bin to emuNAND.bin

3) Go back into Decrypt9 and flash emuNAND.bin (formerly sysNAND.bin) to your emunand. The end result is that both your sysnand and emunand will be clones of each other on 9.2 again.

4) This next step is very important: DO NOT FLASH NAND.BIN TO SYSNAND WITH DECRYPT9. Your emunand did not have a9lh installed to it, so if you do a direct flash of an image of your emunand to sysnand, you will end up with an updated sysnand and no a9lh. And that would be no fun at all.

Instead, what you do is leave Decrypt9 and run arm9loaderhax.3dsx. The installer has a feature where, if a NAND.bin exists on your SD card, it will flash it to your sysnand, and then install a9lh to your newly flashed sysnand. That way, you will end up with your emunand successfully swapped to your sysnand, and a9lh will be there to keep you from becoming a fully updated no-hacks peasant. The NAND.bin install takes somewhat longer than Decrypt9 does, so sit back and watch the memory addresses zip on by. Or go find something to eat instead. It will reboot automatically when the process is finished.

5) Now that you're done with the swap, you need to make sure your CFW is set to boot your sysnand by default. AuReiNand users should hold Select on boot then toggle updated sysnand to yes, and CakesFW users should hold L on boot and be sure that sysnand boot is selected. Selecting the a9lh detection/FIRM writes blocking patches is also HIGHLY recommended. That will keep future updates from overwriting arm9loaderhax. Either way, once you're done selecting your patches, you can continue booting the cfw.


And that's it! Your sysnand and emunand are swapped and you're now a cool kid instead of being a poor guy stuck on 10.7 with no hacks to his name! You might want to make one more sysnand backup at this point, since the new backup that you create will have a9lh preinstalled to FIRM0 and FIRM1 this time around. That way you can restore without fear in the event you find yourself in trouble one day in the future.

 

[drgoku282]

Thanks for the tutorial, worked flawlessly on my N3DSXL and 2DS.

 

[blackalabi]

Awesome guide, easily switched my sys and emuNand on my N3DSXL.

 

[Rustic]

Looks cool to me. Maybe gonna try this later this week.

For now, just fix the tiny emuNAND typo in step 2

 

[Ecko3351]

How do you uninstall menuhax? I already have arm9 installed but getting into homebrew launcher from sysnand is giving me trouble. Nothing boots up in the homebrew launcher....

Edit
Also holding L for me boots into menuhax instead of sysnand. R for me is sysnand.

 

[Rustic]

How do you uninstall menuhax? I already have arm9 installed but getting into homebrew launcher from sysnand is giving me trouble. Nothing boots up in the homebrew launcher....

Edit
Also holding L for me boots into menuhax instead of sysnand. R for me is sysnand.

Just change your theme and it's removed.

 

[goudja]

great guide, i will to try, but should i uninstall A9LH (by restore a sysnand backup made before running arm9loaderhax.3dsx) before beginning this guide, thanks, sorry for my bad English.

 

[FenrirWolf]

great guide, i will to try, but should i uninstall A9LH (by restore a sysnand backup made before running arm9loaderhax.3dsx) before beginning this guide, thanks, sorry for my bad English.

No reason to uninstall a9lh

 

[Seriel]

One thing im concerned about with this, before syNAND was a kind of safety net if emuNAND failed, now won't that net be gone? So if something goes wrong, you're screwed.

 

[FenrirWolf]

One thing im concerned about with this, before syNAND was a kind of safety net if emuNAND failed, now won't that net be gone? So if something goes wrong, you're screwed.

So long as FIRM0/FIRM1 are intact, you can screw up the rest of your NAND however you like.

That being said, swapping sysnand and emunand is something you should only do if you want to do it, and if you are aware of the best practices to follow so that you won't inadvertantly overwrite a9lh and leave yourself dead in the water. If you'd rather stay on emunand then stay on emunand. That's a perfectly viable choice too.

 

[Seriel]

So if you thoroughly screwed your 3ds up big time and ended up bricking it, but FIRM0/FIRM1 are intact you can restore it with A9LH?

 

[FenrirWolf]

Yup. FIRM0 and FIRM1 are where the a9lh exploit and payload live. So as long as those are intact, you can still boot into your emunand or boot directly into Decrypt9 and perform a NAND restore. That's also why I suggest making another NAND backup after performing the sysnand and emunand swap. That way if you ever brick your sysnand on accident, you can restore that backup and you won't lose a9lh in the process.

Or since you can still access emunand even with a bricked sysnand, you can use that to run arm9loaderhax.3dsx again. As detailed in the guide, that will flash NAND.bin to sysnand and then reinstall a9lh, so you can always go that route if you find yourself unsure of if your most recent sysnand backup already has a9lh in it or not.

So far the only major benefit to having everything on sysnand is that DS and Virtual Console stuff is easier to work with, as you don't have to install your games and patches to both emunand and sysnand. That and maybe 1-2 seconds faster boot compared to emunand. If none of that bothers you very much, you won't really lose anything by sticking with emunand as your primary base of operations.

 

[Rustic]

So if you thoroughly screwed your 3ds up big time and ended up bricking it, but FIRM0/FIRM1 are intact you can restore it with A9LH?

The idea is that aureinand should prevent anything from touching those so you'd be able to launch a recovery system even if the system is otherwise completely unusable.
But i don't think a9lh has been around for long enough and doesn't have enough users to really have any meaningful data on it. And no "real" brick situations.

 

[sausbaus]

If you're using AuReiNand, you'll need to hold L when booting the console to start your 3DS using firmware90.bin.

This isn't working for me. I just get a black screen while trying to boot. My sysNAND is on 9.2 and I do not have menuhax installed. Can't seem to figure out what the problem is.

 

[FenrirWolf]

This isn't working for me. I just get a black screen while trying to boot. My sysNAND is on 9.2 and I do not have menuhax installed. Can't seem to figure out what the problem is.

The most likely culprit is that you don't have firmware90.bin or it's not in the rei folder where it ought to be. What happens when you hold R to boot?

 

[sausbaus]

The most likely culprit is that you don't have firmware90.bin or it's not in the rei folder where it ought to be. What happens when you hold R to boot?

I wish it were as simple as that, but unfortunately I do have the firmware90.bin file in my rei folder. Holding R on boot brings me to sysNAND, but I can't start Decrypt9 via HBL.

 

[FenrirWolf]

Boot into sysnand by holding R, go into the homebrew menu, then run the Menuhax installer and choose the uninstall option. Sometimes just changing themes isn't a deep enough clean to truly be rid of it.

After that, see if holding L will get you in.

 

[sausbaus]

Boot into sysnand while holding R, go into the homebrew menu, then run the Menuhax installer and choose the uninstall option. Sometimes just changing themes isn't a deep enough clean to truly be rid of it.

After that, see if holding L will get you in.

I've tried this a couple of times already and it still doesn't wanna work.

 

[FenrirWolf]

That's pretty odd. You don't happen to have CTRBoot9 set up with anything assigned to the L button, do you? I'm also reminded of another person I helped out who had to hold both L and R instead of just L to boot into his sysnand with the 9.x FIRM for some reason.

If those things don't solve the issue, the next thing I would try is redownloading all the AuReiNand stuff and replacing everything with all the new files. Then if that doesn't work I would recompile arm9loaderhax.3dsx with the latest source and install that again (making sure there's no NAND.bin on the card because you don't wanna flash that right now).

 

[sausbaus]

That's pretty odd. You don't happen to have CTRBoot9 set up with anything assigned to the L button, do you? I'm also reminded of another person I helped out who had to hold both L and R instead of just L to boot into his sysnand with the 9.x FIRM for some reason.

If those things don't solve the issue, the next thing I would try is redownloading all the ReiNand stuff and replacing everything with all the new files. Then if that doesn't work I would recompile arm9loaderhax.3dsx with the latest source and install that again (making sure there's no NAND.bin on the card because you don't wanna flash that right now).

No, I've never used CTRBoot9 before.

I did just notice however, that after uninstalling menuhax and then going to set a theme, it doesn't display the "creating theme management information" message. Seems like it could have something to do with this issue.

EDIT: Booting while holding R + L still results in a black screen.