Old 8-bit binaries taken apart byte by byte and commented, with the tools to rebuild them: nothing gets claimed that the binary does not show, and the source has to give the original back, byte for byte. Right now that means 64 MSX games.
Tools that came out of doing things with the MSX: for the Yamanooto cartridge, for networking, for editing graphics and files, and a couple from outside the MSX. Each one links to its repository, with the code and the instructions.
Builds the image for a Yamanooto cartridge out of your own ROMs: a menu on the cartridge and the games behind it. It tells each game’s mapper by its SHA1, converts the ASCII8/ASCII16 ones, and patches Metal Gear, Metal Gear 2 and The Maze of Galious (also the Enhanced) on the fly so they save the game to the cartridge’s flash.
GUI for Windows, Linux and macOS · also from the command line
Real TCP/IP networking for MSX software running in openMSX: a device inside the emulator that uses the host computer’s network, and a TSR on the MSX offering the standard UNAPI interface. hget, telnet or sntp run unmodified. It is now part of openMSX: the device was merged into the official emulator.
DNS · up to 4 TCP connections and 4 UDP
Repositorymerged into openMSX, PR #2147, 2026-08-10
Moves files between the PC and a real MSX over the network, both ways and also from MSX to MSX. Everything speaks plain HTTP/1.0, so the same folder can be browsed from a web browser. The MSX finds the servers on the local network by itself, without typing an IP.
server for Windows, Linux and macOS · NT.COM client of about 8.5 KB
Hex editor and viewer for the MSX2, in 80 columns. It opens any file on the disk, shows it in hex and ASCII, searches for hex strings and edits bytes; it saves to a new copy unless you confirm you want the original overwritten. Only a window of the file is kept in RAM, so it opens files of up to 720 KB.
MHEXED.COM of about 10 KB · tested in openMSX
Graphics editor for the MSX: tiles, 32×24 maps and 8×8 and 16×16 sprites, with the TMS9918A’s limits checked while you draw (two colours per tile row, one colour per sprite). It imports a picture and cuts it into tiles, and exports to JSON, to C arrays for MSXgl and to binary.
portable executable of about 8 MB
Searches for ROMs on archive.org, the Internet Archive and CDRomance, and returns the link to the actual file. When the game sits inside a TOSEC pack in a single .zip, it looks inside the zip and links the game, without downloading the whole pack.
120+ systems · inline mode too
Plays in Morse code the text that reaches an ATmega328p — the microcontroller of the Arduino Uno — through its serial port.
tested on Arduino Uno, Leonardo, a breadboard 328p and an ATtiny85