Skip to content

Dumping romFS for game modding

The term "romFS" means "ROM filesystem". Dumping the romFS of a game means that you dump the contents of a game (the folders and files a game consists of internally) into an easily readable format, so that you can create game mods and/or modify other aspects of a game.

NX Dump Client Setup

Note

These steps are needed to configure nxdt_host, a client program for dumping games directly to your PC. THIS IS HIGHLY RECOMMENDED FOR THIS SECTION! If you'd still like to dump to your console's SD card and copy the files to your PC later, you can skip this section.

Section I - Requirements

Section II - Instructions

  1. Launch HBMenu on your Switch, and open NXDumpTool (nxdt_rw_poc.nro).
  2. Connect your console to the PC via USB (with nxdt open).
  3. Run Zadig on your PC. Go to Options and check the List all devices option.
  4. In the top dropdown menu, select the nxdt_rw_poc USB device.
  5. Change the Driver dropdown on the right to libusbK (vX.X.X.X).
  6. Click on Install Driver. Wait for the installation to finish.
  7. Extract nxdt_host.7z using 7-Zip. If you don't have 7-Zip, you can download it here.
  8. In the extracted files, find and run nxdt_host.exe
  9. Set the output directory by pressing Choose and selecting a folder of your choice.
  10. Click Start server.

You're ready to start! Proceed to the Dumping the romFS section below.

Section I - Requirements

Section II - Instructions

  1. Install NX Dump Client either via the AUR on ArchLinux based distros, or via Flathub on others.
  2. Start NX Dump Client on your PC.

You're ready to start! Proceed to the Dumping the romFS section below.

Section I - Requirements

Section II - Instructions

  1. Install python3 using the provided link above.
  2. Open a new terminal window and cd (change directories) into the folder that contains the nxdt_host python script.
  3. Start the script by running python3 nxdt_host.py.

You're ready to start! Proceed to the Dumping the romFS section below.

Dumping the romFS

Section I - Instructions

  1. Launch sysCFW via hekate. If you followed our guide for CFW setup, this is the Atmosphere PKG3 sysMMC button.
  2. Launch HBMenu and open NXDumpTool (nxdt_rw_poc.nro).
  3. Select user titles menu
  4. Find the game you want to dump and select it.
  5. Select nca / nca fs dump options
  6. If you're dumping to a PC, set output storage: to usb host (pc)
  7. Select dump base application
  8. Select Program #0: <string of characters>
    • Very few games may have more Program #'s, you may dump only one or all of them.
  9. Select FS section #2: RomFS
    • If you want to dump the ExeFS do FS section #1: ExeFS
  10. Set use base/patch title to no if you don't want it to apply updates on top of the base.
  11. Select start nca fs section dump
  12. If you set output to usb host (PC), make sure NX Dump Client/nxdt_host is open on your PC, then connect your Switch. Dumping will begin.

Section I - Instructions

  1. Launch sysCFW via hekate. If you followed our guide for CFW setup, this is the Atmosphere PKG3 sysMMC button.
  2. Launch HBMenu and open NXDumpTool (nxdt_rw_poc.nro).
  3. Select user titles menu
  4. Find the game you want to dump and select it.
  5. Select nca / nca fs dump options
  6. If you're dumping to a PC, set output storage: to usb host (pc)
  7. Select dump update to dump an update, or dump dlc to dump DLC for the game.
  8. Select Program #0: <string of characters>
    • For DLC select Data #0: <string of characters>.
    • On this page you may press L and R to change which DLC for the chosen game you are dumping.
  9. Select FS Section #2: Patch RomFS
    • For DLC this is FS Section #1: RomFS.
    • If you want to dump the ExeFS do FS section #1: ExeFS
  10. Set use base/patch title to no if you don't want it to dump the base with the update.
    • This may not be an option for DLC.
  11. Select start nca fs section dump
  12. If you set output to usb host (PC), make sure NX Dump Client/nxdt_host is open on your PC, then connect your Switch. Dumping will begin.

Organizing Dumps

By default, NX Dump Client will output your dumps to $HOME/Downloads, you can however change this to wherever you like. Either way, you can now move your game dumps from the output folder to anywhere you find convenient.

Merging Split Files

Info

If you chose to dump to your SD card, files over 4GB in size will be split to accommodate for FAT32 filesystem restrictions. If you would like to merge them into one file, follow this section. Those who chose to dump to PC can skip this section.

Section I - Requirements

  1. Access your SD card and copy your game dump(s) to an easily accessible location on your PC.

    • You can access your SD card via hekate by going to Tools > USB Tools > SD Card and plugging your Switch into your PC via USB.

  2. We will use a terminal/command prompt window on your PC to merge the dumped files.

Select the right tab for your computer's operating system:

Section II - Instructions

  1. Open File Explorer, and navigate into the folder where you placed your split file.

    • Make sure the dumped files are in a dedicated folder, that doesn't contain any other files.

  2. Click on the address bar in File Explorer.

  3. Type in cmd and hit Enter. A command prompt window should open.

  4. To merge a file, type in copy /b * "[name].<file extension>" and hit Enter. (Replace [name] with the filename of the file you are merging)

  5. That's it! Your file is now merged.

Section II - Instructions

  1. Open your desired file manager, and navigate into the folder where you placed your split file.

    • Make sure the dumped files are in a dedicated folder, that doesn't contain any other files.

  2. Right click anywhere in the folder and open a terminal window in the current folder.

    • You can also simply open a terminal window and cd into the directory containing the split file.

  3. To merge a file, run cat * "[name].<file extension>" and hit Enter. (Replace [name] with the filename of the file you are merging)

  4. That's it! Your file is now merged.