getROM

Tools and utilities from dumping the ROM from an RCX, which is often then used by RCX emulators.

Obtaining a ROM Image

Based on both original instructions posted here and accessed via archive.org as well as more recent documentation (plus a patch file) posted on the RCXSimulator site.

Here is one set of steps you might follow to obtain an image:

1. Get and compile send.c.

   • Per the source code comments, this should compile under IRIX, Linux, and Solaris with cc send.c -o send

2. Make a copy of the firm0309.lgo firmware file.

3. Apply the "getROM.diff" patch to this copied firmware file.

   The individual modifications applied to the firmware file are follows:

   Search for S11396D0, delete that line, and replace it with:

   S11396D0B2D6AEA0ACB6A7A49BB8BFD0B23CAE3055
   

   Search for S11396F0, delete that line, and replace it with:

   S11396F0A998BFF0AD6AA21CAF50AABCA38899FA7E
   

   Search for S113BFD0, delete that line, plus the two that follow, and replace them with:

   S113BFD06E7E001C6E76001D6B86BFC06E7E001EDA
   S113BFE06E76001F6B86BFC2FECB5A00A1F600001E
   S113BFF06B06BFC26DF66B06BFC06DF65A00BB9AE6
   

   Save this file.

4. Download the new firmware file to the RCX. Any standard RCX firmware download tool should suffice.

   • If you want a Unix firmware downloader with C source, get and compile firmdl.c.

5. Get and perhaps edit getrom.pl. As is, this program assumes you are running under some flavor of Unix and that you have Perl 5 installed. It also assumes that the send program is in your path.

   • This also appears to work under Cygwin on Windows

6. Run getrom.pl and redirect its stdout to a file. When getrom.pl completes, this file should contain an image of the ROM in s-record format.

7. Don't forget to reinstall the normal firmware once you've got your ROM image.

Additional Resources

Further information regarding the RCX ROM has been posted on the RCX Internals site.

Alternatives

An open source implementation of the LEGO ROM for the MindStorms RCX is available under the FOSS-RCX-ROM project. When possible use of an extracted LEGO ROM is preferred, as that better guarantees compabitility.

A version of ROM extracted from a LEGO MindStorms RCX 1.0 brick is also available with the LEGO releases posted under the BrickBot Archive repository.