Super Monkey Ball Jr. stores much of its data in a custom filesystem inside the rom. This tool can extract the individual files from an SMB JR rom and also build a rom from the extracted files. Only the US version of the rom is supported.

While the download is for Windows, the source code can be built for other systems too.

Note: Missing files

The provided files_us.txt filelist is missing the names of 15 files. These files won’t be extracted and they will be missing from any rom you build. Since the repacked rom seems to work fine without them, it hasn’t been determined if the files are unused or where the game uses them.

Usage

The tool is meant to be used from the command line. It has 3 operations: unpacking, repacking and checking.

Unpacking rom:

./unpacker.exe u (rom path) (filelist path)

This produces a directory containing all the extracted files, a copy of the filelist file with compression types for each extracted file and a code.bin containing the rest of the rom.

A filelist file is needed to define what files are extracted. Such list is provided with the tool: files_us.txt

Repacking rom:

./unpacker.exe r (directory) (output rom name)

This command produces a rom file from a directory containing the extracted files. The directory must contain a code.bin file, filelist.txt file and all the files mentioned in the filelist.txt

Checking rom:

./unpacker.exe c (rom path) (filelist path)

This command simply checks to see if the list’s files can be found in the rom and prints information about the files.