trapexit/modbin

Modbin is a tool for people developing software for the 3DO, a 1990s video game console. It lets you view and modify the "header" of a 3DO executable file, a chunk of metadata at the top of the file that tells the console how to run the program. You can set things like stack size, priority, version numbers, and flags, and you can also sign executables, which is required for running privileged tasks or libraries on the system. At a high level, you run it from the command line, point it at an input file, and optionally specify an output file. If you just want to see the current header values, you pass the file and it prints them out. If you want to change values, you pass options like --stack or --pri along with a number, and it updates the header accordingly. Changing values on a signed executable means you'll need to re-sign it afterward. The tool supports both "app" and "3do" signing modes, matching what the original 3DO SDK tools offered. This is for anyone working on homebrew 3DO games or preserving old 3DO development workflows. For example, if you're building a 3DO executable with a modern toolchain and need to set the right priority or stack size for the console to run it properly, you'd use this. The original version shipped with the 3DO SDK decades ago, this is a clean rewrite in C that covers all the same features plus RSA signing in one tool. It's a small, focused utility, written in C99, buildable on Linux, macOS, and Windows. The project doesn't aim to be anything beyond a faithful, open replacement for a proprietary tool that's otherwise hard to come by. The README doesn't go into detail on the specific "minor extras" it mentions, but the core value is clear: a single, modern, buildable tool for a niche but still-active retro development community.