This guide is intended for users who want to create their own ROM hacks with DreamNexus.
Table of contents
To get started on RTDX hacking, you need a ROM of Pokémon Mystery Dungeon Rescue Team DX and a file containing decryption keys (prod.keys or keys.txt). If you don't have these files and want to dump them with your Switch, refer to steps 1 and 2, otherwise you can skip to step 3.
<aside> ⚠️ Custom Firmware is considered safe and, in most cases, cannot cause persistent damages to the system if you have backups. However, we are not responsible for any damages or bans that might occur! Text guides are strongly recommended since videos about this subject are often outdated.
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First, you need to setup the custom Firmware Atmosphère on your Switch console. Please follow this guide, which explains all the terminology and walks you through the process step by step: https://nh-server.github.io/switch-guide/
<aside> ❗ Rescue Team DX has online features, so be sure to also follow the guide on how to block communication with Nintendo's servers. If blocking the servers entirely is not an option for you, avoid using in-game features like online rescues which need an Internet connection. Some ROM hacks might include features that connect to the internet, so keeping your Switch disconnected e.g. with Flight Mode is not recommended or required, since blocking Nintendo's servers is enough to avoid bans.
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If you have physical version of Rescue Team DX, refer to this guide. You can ignore the Gathering Dump Info section.
If you have a digital version, follow this guide instead. You can ignore Extracting data from NSP and later sections.
If the dumping process was successful, you should now either have a .xci or .nsp file. Copy the file somewhere to your computer.
Install and open DreamNexus, then click the "≡" button on the top right and open Settings. Under Rom Settings, click Select ROM file... and select the prod.keys file. then select the .xci or .nsp file (the prod.keys file should be part of your backup if you followed step 1; if you don't have prod.keys, follow these steps again).
If you want to test your ROM hack on console, select Atmosphère under Build Settings - Output file structure for:. If you want to use an emulator, select Yuzu Emulator instead.
Click Apply and you are ready to create your first modpack.