Before we begin, very important note:

1. This tutorial is for firmware <=9.2
   However, if you're able to get the romfs and exefs decrypted from other sites, it'll serve your purpose.
2. The example I'm using is for Pokemon
3. If you set HANs to a different region from your 3DS, you won't be able to connect online
4. This is primarily for game-breaking patches, rather than online use.
5. Make sure you're using the newest of newest HANs, the one that allows eshop use for uses under FW10.

Other tutorials you'll need to refer to:
Decrypting and extracting CIA
Decrypting and extracting Rom


Step 1:
Decrypt and extract the Update CIA. (you can find it on a certain site, don't ask)
Make sure you extract the exefs/code.bin option and get a .code.bin file. (it is gonna be around 5312 KB)

Rename this .code.bin from the Update file as <Title ID>.code
Example: 0011C500.code

You're also going to need the extracted romfs folder from the update file.

Step 2:
Extract the romfs from the game.

Step 3:
Paste the romfs from the update file into the romfs of the game.
When it prompts, replace everything.

Step 4:
Rebuild romfs as a single file.
Name it as <Title ID>.romfs
Example: 0011C500.romfs

Step 5:
Create a hans folder on the root of your SD card.
(Example sd:/hans DO NOT TOUCH THE HANS FOLDER IN THE 3DS FOLDER)

Step 6:
Copy both the .code and .romfs file into the sd:/hans

Step 7:
Launch the game in HANs,
Set the region to be same region as your 3DS
Set the code -> SD and romfs -> SD to Yes

Proof (of sorts)

Spoiler

Don't ask me why Jeff is a female; not my cartridge.

Enjoy!
(such a pity, I wanted to connect to Korean Pokemon Wifi; probably won't work because Secureinfo mismatch)

Special thanks:
Everyone who found and exploited the exploits
Gudenaurock's Layered FS guide that gave me the idea
Asia81's tutorial allowed for me to do the test.

 

[Queno138]

How do I decompress it?

When you dump everything using the Hack Pack. There should be an option to decompress it.
(this is during the dump)



Also, make sure you're using the newest HANs 2.5

It doesn't require you to remove 1000bytes from the romfs

 

[WiseHorror]

I've been searching for a decrypted update file for EUR Alpha Sapphire and X/Y for hours, but I only found encrypted cia update. It sucks to have both my 3DS's on 10.3. If only there was a way to extract cia files without needing to be on <=9.2

 

[Queno138]

I've been searching for a decrypted update file for EUR Alpha Sapphire and X/Y for hours, but I only found encrypted cia update. It sucks to have both my 3DS's on 10.3. If only there was a way to extract cia files without needing to be on <=9.2

You'll probably have to go over to the certain ISO site and request for the dumped and decrypted files.

I saw that someone was uploading romfs for rom hacks.
It may be possible to set up a thread to collect romfs and code.bin there

 

[WiseHorror]

You'll probably have to go over to the certain ISO site and request for the dumped and decrypted files.

I saw that someone was uploading romfs for rom hacks.
It may be possible to set up a thread to collect romfs and code.bin there

EDIT: Never mind... I'm just dumb

 

[Neru]

When you dump everything using the Hack Pack. There should be an option to decompress it.
(this is during the dump)



Also, make sure you're using the newest HANs 2.5

It doesn't require you to remove 1000bytes from the romfs

I did decompress it, and also have the latest Hans. Still getting the same error. I guess it doesn't work for Smash at all.

 

[Queno138]

I did decompress it, and also have the latest Hans. Still getting the same error. I guess it doesn't work for Smash at all.

I'll give it a try when I'm free ><

 

[Acryt]

Will love to try this when I find a way to get my hands on the files for it. Don't have 9.2

 

[Asia81]

I will upload all decrypted eur updates where you know.
Can do it for usa too, but need to have cia (If you have, send me the link where you know)

 

[SomeGamer]

I will upload all decrypted eur updates where you know.
Can do it for usa too, but need to have cia (If you have, send me the link where you know)

Thanks a lot! Could you PM me the links once you're done? Also, could you do this with DLC you own?

 

[Asia81]

No link, you will have to check where you in the cia section
And there is no DLC in pokémon, right ?

 

[Acryt]

No link, you will have to check where you in the cia section
And there is no DLC in pokémon, right ?

Thank you, and nope.

 

[plushifoxed]

I will upload all decrypted eur updates where you know.
Can do it for usa too, but need to have cia (If you have, send me the link where you know)

Do you think you could decrypt Smash (USA)'s updates? I'll PM you the details over there.

 

[Asia81]

If you have the cia, send me it

 

[plushifoxed]

If you have the cia, send me it

I PMed it to you on "there". If you can't download it from that site, I could reupload it to my personal site temporarily... Or if you'd prefer I just PM it to you over here instead.

 

[Acryt]

Im patiently waiting for the pokemon ones XD

 

[Asia81]

EUR Onlines, check the thread where you know:
[Jheberg][Updates][EUR/USA] Decrypted Files from Mario/Pokémon/Zelda/SSB Updates

@Roxie Mika
@Acryt
@SomeGamer

 

[Acryt]

Can't get this to work with ORAS, game simply won't ever go to menu. Can't figure out why. I'm using PK3DS to pack the files with all the update romfs.

Also the code.bin needs to be merged correctly with the original code.bin from the game i'm guessing? Which is not something I've done before. Because just placing it in the folder of HANS doesn't seem to work, and not going to because it's only ~2800kb. When I do get the proper ~5312kb code.bin, HANS gets the error that would lead us to this thread:
https://gbatemp.net/threads/trouble-running-custom-code.400822/

Game doesn't load either without a code.bin, so I've no idea.

If anyone gets this to work with the files Asia has uploaded, please post back.

 

[~Poke~]

Can't get this to work with ORAS, game simply won't ever go to menu. Can't figure out why. I'm using PK3DS to pack the files with all the update romfs.

Also the code.bin needs to be merged correctly with the original code.bin from the game i'm guessing? Which is not something I've done before. Because just placing it in the folder of HANS doesn't seem to work, and not going to because it's only ~2800kb. When I do get the proper ~5312kb code.bin, HANS gets the error that would lead us to this thread:
https://gbatemp.net/threads/trouble-running-custom-code.400822/

Game doesn't load either without a code.bin, so I've no idea.

If anyone gets this to work with the files Asia has uploaded, please post back.

I'm guessing you got an incomplete download, because I grabbed the decrypted update from that place just a moment ago and it gave me a 5,312KB code.bin.

That said, I'm stumped on how to merge this code with the star sapphire code... is there any way to unpack it? Or should I just be getting diffs with a hex editor?

 

[Asia81]

I have the USA ready for upload, not before 1 hour I guess

 

[WiseHorror]

I just merged my Alpha Sapphire romfs with update 1.4 romfs, and placed 0011C500.code on hans folder, as well as 0011C500.romfs. Can't connect to internet, Error 002-0120. Even though on file select screen it says Version 1.4