Hacking Sys/EmuNand linking technical background

[w0dash]

Hello,

it is well known that the system and emulated nand are linked after creation and unlinked after formatting one of them.

Can someone explain in which way they are connected, as they don't share the same memory partition?

 

[w0dash]

Push.

 

[zoogie]

Here is a little visual representation of the unlinking concept I just whipped up. Hope it helps some.

 

[lPolarisl]

Let's say you have your sysnand. You decide to have an emunand. The program creates an emunand on your SD card, this just copies your 3DS's firmware to the SD card, your personal files (games, pictures, or anything not related) stay on the SD card.
Now, every 3DS has a custom "signature", this is why you can't play another 3DS's 3dsware, the "signatures" don't match up.

Your emunand is a clone of your sysnand, therefor they have the same "signature", so if you meddle with one's personal files, it is in conflict with the other's personal files. Because the filesystem wasn't designed to be used by two different 3DSs.

When you format one of your nand's, you change that nand's "signature", as such it will now use different files. You'll be running two different 3DS on the same system.

I don't know if I was clear, feel free to ask away

everyone else : correct me if I made any mistakes.

 

[thorasgar]

This needs to be a sticky.

 

[scynetic]

When formatting sysnand or emunand, do you always pull out the SD card? Is there a best spot to do this in the format process?

 

[cearp]

it's just one smaller little file called movable.sed that is stored in nand.
it is the same file that gets transferred when you system transfer, so that all your old content will work on the 3ds you changed to.
when you format you get a new moveable.sed file.

 

[thorasgar]

When formatting sysnand or emunand, do you always pull out the SD card? Is there a best spot to do this in the format process?

When you format sysnand you pull the SD card out before you confirm the format.

I have never tried pulling the card out while formatting emunand. Considering emunand is on the SD card I think it rather unwise, but what the hell give a try and see what happens.

 

[cearp]

When you format sysnand you pull the SD card out before you confirm the format.

I have never tried pulling the card out while formatting emunand. Considering emunand is on the SD card I think it rather unwise, but what the hell give a try and see what happens.

it crashes

 

[VerseHell]

Formatting the console doesn't format the sd card, so you don't even have to pull it out.

 

[cearp]

Formatting the console doesn't format the sd card, so you don't even have to pull it out.

it doesn't format the sd card no, but it does get rid of all the data that was tied to the 3ds (to that nand), like games, save, etc

 

[VerseHell]

Didn't know that, thanks for the information.

 

[cearp]

Didn't know that, thanks for the information.

that is why some people say to remove the sd card when you system format in settings, if the sd card is not there, it cannot delete your stuff
(but you will still get a new movable.sed file in nand) - so the stuff that would have been deleted would no longer work with this nand -- but if you have another nand that you did not format, and you have just 'unlinked' them, then the stuff will work with the other nand...
i hope that makes sense, maybe i explained it badly

 

[Kohmei]

Is it true you can't make your own .cia files once you unlink? It seems to be the only downside to unlinking

 

[cearp]

Is it true you can't make your own .cia files once you unlink? It seems to be the only downside to unlinking

well, you cannot decrypt your own stuff no, not if you extract your movable.sed file and put it on the sd card, so it will be used when decrypting
but if you use something like FunkyCIA, you will be ok, because it does not need to decrypt anything

 

[XDM]

in my emunand and sys nand are linked but in my Nintendo 3ds folder theres not 1 folder theres 5. how do i know what belong to 3ds gamedata/dlc and which one is the sysmenu?

 

[FR0ZN]

Here is a little visual representation of the unlinking concept I just whipped up. Hope it helps some.

View attachment 15105

This is strange, I have never unlinked my NANDs but they are seperated. I looked inside the Nintendo 3DS folder and there is only one sub folder in there. I also don't have this unwrapping bug everybody is tallking about for CIA titles. The only thing I noticed after I created my emuNAND back at the time, was that the WiFi configuration carried over to sysNAND, but I was able to delete it there and let it remain for emuNAND.
But apart from that I never ever formatted either NAND.

EDIT: Another Thing I noticed is that, when I install a CIA on emuNAND, I can see it in sysNAND. And I remember that I tried to create a Homebrew folder in emuNAND to put all my CIAs in there, but it didn't carry over to sysNAND, it just reset that Setup for both NANDs and I actually had to create a folder on both NANDs for them to stay like this.

 

[Maximilious]

This is strange, I have never unlinked my NANDs but they are seperated. I looked inside the Nintendo 3DS folder and there is only one sub folder in there. I also don't have this unwrapping bug everybody is tallking about for CIA titles. The only thing I noticed after I created my emuNAND back at the time, was that the WiFi configuration carried over to sysNAND, but I was able to delete it there and let it remain for emuNAND.
But apart from that I never ever formatted either NAND.

EDIT: Another Thing I noticed is that, when I install a CIA on emuNAND, I can see it in sysNAND. And I remember that I tried to create a Homebrew folder in emuNAND to put all my CIAs in there, but it didn't carry over to sysNAND, it just reset that Setup for both NANDs and I actually had to create a folder on both NANDs for them to stay like this.

That sounds a little messed up. I would backup your SD card and emuNAND with emuNAND Tool, remove SD card, format sysNAND again, format emuNAND, restore emuNAND from backup. Then you can copy over one of the two folders to see which one is the correct one for emuNAND.

 

[FR0ZN]

That sounds a little messed up. I would backup your SD card and emuNAND with emuNAND Tool, remove SD card, format sysNAND again, format emuNAND, restore emuNAND from backup. Then you can copy over one of the two folders to see which one is the correct one for emuNAND.

There is no second folder ... only one folder in the "Nintendo 3DS" folder

 

[Nurio]

I can also recall there were downsides to unlinking. What are these downsides again?