Archived Firmware and ROM Images for the LEGO MindStorms RCX

NOTE: This is not a repository for current firmware images; for the latest firmware versions for a given project, please check the given project’s site under the BrickBot organization on GitHub.

Official Firmware

Official LEGO® Firmware and ROM Files

Third-Party Firmwares

Platforms for Creating Alternative Firmware

Firmware for Alternate Programming Languages

RobotC (Dick Swan) – Designed for programming the RCX using a C-like language

BrickOS / Bibo – Designed for programming the RCX using languages supported by GCC

pbForth – Designed for programming the RCX using Forth

Java Virtual Machine (JVM) Firmware

LeJOS – Designed for programming the RCX using Java

“Appliance” Firmware

These firmware release can be loaded on the RCX and will run as-is, with no additional programming needed on the computer side. LDCC (LEGO Digital Command Control) – Designed for using with DCC (DCC is typically implemented for use with model trains.)

• Includes both Command Station and Accessory Decoder firmware
• The Command Station capabilities have been incorporated into the latest versions of BrickOS / Bibo

OnScreen Programming – Designed for on-device programing of the RCX

Pocket Programmer – A more advanced and completely rewritten implemantation based on OnScreen Programming

Firmware Information Links

• Lego RCX Firmware Disassembler
• PBrick Firmware Info
• jverne Firmware README
• Francesco Ferrara Lego Page

Historical Lists of Known Firmware/Languages

• Quick Start Guide
• Old listing of various programming languages for the RCX, retrieved via archive.org