Caro 1024KB Expansion RAM
This page was last modified 12:21, 26 December 2021 by Mars2000you. Based on work by Gdx and Grauw.


This Expansion RAM was designed by Kamil Karimov (a.k.a Caro). It is an internal memory mapper of 1MB (1024kB) for the following MSX models:

These machines have a memory-mapper on board, even the MSX1 models, and the BIOS is patched by Yamaha to initialise the mapper in the order (3, 2, 1, 0) like the MSX2 BIOS does.

Before buying this extension, make sure the connector is present on the mainboard. It seems that some of these MSX computers do not have this connector.

The expansion board is sold by Alexey.


1024KB Expansion RAM Board released by Alexey


  • BMMS (Bigger Memory Mapper Selector)
  • CHKMEM.BIN (Utility that displays the slots of RAM, memory mappers and MegaRAM by LARK)
  • Mapper info (by Yukke)
  • MEGA16.COM (Loader for MegaROMs with 16k mapper)
  • MEMTEST.COM (Memory mapper RAM tester by Masatoshi Fujimoto)
  • TESTMAP.COM (Memory mapper RAM tester by Marteen)
  • SofaRom (MegaROM and ROM loader by Louthrax)