A complete reverse‑engineering of the TI‑84 Plus operating system is now available online.
The project, led by hobbyist Siraben, dissected the calculator’s firmware, reconstructed the source code and published it on a dedicated website. The repo includes annotated assembly, build scripts and documentation of the boot process. It also provides a brief guide for compiling custom programs.
For a device that still ships in schools, having the OS source lowers the barrier for teaching low‑level programming and enables security audits. It also gives hobbyists a legal foothold to create extensions without violating the vendor’s license.
The effort is another reminder that even legacy hardware can become open for tinkering when enough eyes turn it inside out.