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kartdlphax is an exploit for the Download Play mode of Mario Kart 7. It can be used with universal-otherapp to install custom firmware on target devices.
In order to follow these instructions, you will need the following:
- A second 3DS with custom firmware (the **source 3DS**) that is the same region as the 3DS you are trying to modify (the **target 3DS**)
- A physical or digital copy of Mario Kart 7 that is the same region as both consoles
- An SD card for both devices
### 必要なもの
On the **source 3DS** (the 3DS with custom firmware):
* The latest release of [SafeB9SInstaller](https://github.com/d0k3/SafeB9SInstaller/releases/download/v0.0.7/SafeB9SInstaller-20170605-122940.zip) (direct download)
* The latest release of [boot9strap](https://github.com/SciresM/boot9strap/releases/download/1.4/boot9strap-1.4.zip) (direct download)
* The latest release of [standard Luma3DS](https://github.com/LumaTeam/Luma3DS/releases/latest) (the Luma3DS `.zip` file)
1. Copy kartdlphax's `plugin.3gx` to the following directory on the **source 3DS**'s SD card, depending on the **region of your copy of Mario Kart 7**:
- USA: `luma/plugins/0004000000030800`
- EUR: `luma/plugins/0004000000030700`
- JPN: `luma/plugins/0004000000030600`
- Create the `plugins` and `00040000...` folders if they do not already exist
1. Eject the SD card and put it in the **source 3DS**
#### Section II - Prep Work (target 3DS)
1. Insert the SD card of your **target 3DS** in your computer
1. Copy `boot.firm` and `boot.3dsx` from the standard Luma3DS `.zip` to the root of your SD card
- If the source 3DS freezes at this point and you are using a cartridge, try [installing the cartridge to the system](dumping-titles-and-game-cartridges#installing-a-game-cartridge-directly-to-the-system)
1. On the **target 3DS**, open the Download Play application (![]({{ "/images/download-play-icon.png" | absolute_url }}){: height="24px" width="24px"}), then select "Nintendo 3DS"
1. Join the group created by the **source 3DS**
1. Select "Start" on the **source 3DS** once it has detected the **target 3DS**
+ If your target 3DS shuts down when you try to power it on, ensure that you have copied `boot.firm` from the Luma3DS `.zip` to the root of your SD card