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custom-install is a new homebrew that allows you to install 3DS CIA files to your SD, with just a PC


The Nintendo 3DS homebrew scene is still alive and kicking, with a new and very useful project by the simple name of custom-install. This tool allows you to take a .cia backup file, and install it to an SD card, removing the hassle of installing your games through the normally slow process on the 3DS itself. The process to get it up and running can be viewed below, straight from the project's GitHub page, along with the GBAtemp discussion topic.

  1. Dump boot9.bin and movable.sed from a 3DS system.
  2. Install pycryptodomex:
  • Windows: py -3 -m pip install --user --upgrade pycryptodomex
  • macOS/Linux: python3 -m pip install --user --upgrade pycryptodomex
  1. Download the repo (zip link or git clone)
  2. Run with boot9.bin, movable.sed, path to the SD root, and CIA files to install (see Usage section).
  3. Download and use custom-install-finalize on the 3DS system to finish the install.
Linux users must build wwylele/save3ds and place save3ds_fuse in bin/linux.

movable.sed is required and can be provided with -m or --movable.

boot9 is needed:

  • -b or --boot9 argument (if set)
  • BOOT9_PATH environment variable (if set)
  • %APPDATA%\3ds\boot9.bin (Windows-specific)
  • ~/Library/Application Support/3ds/boot9.bin (macOS-specific)
  • ~/.3ds/boot9.bin
  • ~/3ds/boot9.bin
A SeedDB is needed for newer games (2015+) that use seeds.
SeedDB is checked in order of:

  • --seeddb argument (if set)
  • SEEDDB_PATH environment variable (if set)
  • %APPDATA%\3ds\seeddb.bin (Windows-specific)
  • ~/Library/Application Support/3ds/seeddb.bin (macOS-specific)
  • ~/.3ds/seeddb.bin
  • ~/3ds/seeddb.bin
Use -h to view arguments.


py -3 -b boot9.bin -m movable.sed --sd E:\ file.cia file2.cia
python3 -b boot9.bin -m movable.sed --sd /Volumes/GM9SD file.cia file2.cia
python3 -b boot9.bin -m movable.sed --sd /media/GM9SD file.cia file2.cia

:arrow: Source
:discuss: GBAtemp Discussion Thread
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