3DS [HowTo] Inject headers into scene roms to play online


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May 2, 2005
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The Moon
I've finally decided to do my own take on a guide for injecting headers into scene roms. If you're one of those who are lost when it comes to using headers on your roms to play online, then this guide will clear things up for you. If anyone has suggestions for the guide, let me know! This guide will be aimed towards Gateway users, it may be the same for other 3DS flashcards. Sky3DS users can't dump game carts unless they have a 3DS on 9.2 or below that can use Gateway mode.

As you may or may not know, scene roms need a header to play online. It just takes a small process to inject one.
Read through the short FAQ below before getting started on the guide.


Table of Contents

1) Q&A
2) Guide on injecting headers
3) Header Trivia
4) List of known online game

Q&A 1)​

What is a header?
A: The general information in a rom, such as the rom size, cart manufacturer, card type, etc. It's a unique ID for your game that shows up when you play online. Think of it as a soul, every 3DS game has it's own soul that makes it unique. Even different copies of the SAME game has it's own soul/header.

Why do we need headers injected into roms just to play online?
A: By default, scene roms don't contain a header. So what's going to show up on Nintendo servers when you play onine? Nothing! A ghost is playing online.

Where can we get headers?
A: There are two kinds of headers, both achieve the same thing. You can use a publicly shared header (RISK OF BAN), or your own header from your dumped rom. It's recommended that you use your own header from a game that you plan on keeping forever.

Would I need to inject a header into my own dumped rom?
A: No, your dumped game contains a header. So your game will show up as if you're playing on the cartridge. There's no work needed when you dump your own game. Just rename the file to .3dz and you're ready to play online. But if you plan on getting rid of the physical copy, then you should clear the header and add your own private header. This will reset the save file.

Can't I just use a pre-patched online ready rom?
A: Yes feel free to do so, that will be the hassle free way of playing a scene rom online. But this will mean using a shared header that many other users are using. Nintendo theoretically will be able to see multiple copies of the same header playing online. So if you want to play it safe, continue on with the guide to learn how to use your own header!


- If you've created a save on a .3ds file, injecting a new header will prevent you from using that save and you will have to start fresh again.

- When playing online, Nintendo may see your header, and other info such as playing a rom. So far, nobody has been banned from Nintendo while playing online with either a shared header or personal header. But this doesn't guarantee that Nintendo wouldn't take action and issue a ban to your system. Play online with a scene rom at your own risk!

The Guide 2)​

Things you will need

1. Gateway Rom Patcher 1.1 Gateway Rom Patcher 1.1 Download

2. A Windows computer, with an SD card reader

Using your own dumped header

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List of known online 3DS games 4)

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Authors Notes

For a long while, I've been confused on how headers work. Even reading through a previously made guide back on GBAtmp, I wasn't entirely sure how it worked. So after spending an entire day researching it and reading comments, I find out that it's way easier than I thought. Injecting headers is a straightforward process that anyone can do. The newer Gateway Rom Patcher does all the work for you, by automatically adjusting the header to the right settings. So that means you can use pretty much a header from ANY game, even offline games. Back then, we had to use a hex editor to edit the info on the header's .bin file to the correct rom size and card type. It was a small learning curve, and confused most of us. Now there's absolutely no need to go through any complicated measures to inject our headers.
I personally use my own header from Mario Kart 7 on all my online scene roms. They all work fantastic! I edited the header to be 4 GB, so it works on all games. You won't have to do this though, I was just being experimental.
I use this ONE header for everything, so when I backup my sav files, I also backup this header with them. I'm never gonna get rid of Mario Kart 7, so my header is safe with me. I've never experienced a single game that didn't boot, or failed to connect online. So the manufacturer is not too important and for the most part, you don't need to change it.
As far as I can tell, if the game works, it will boot up. If it doesn't work, then the game will fail to boot and get an error message from the game.

Big thanks to @mattkimura for the tut :)
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Inactive User
Aug 26, 2015
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I appreciate how you explain in the detail about how headers work as souls for a device lol. Great analogy.