8bits4ever SD-512
This page was last modified 17:45, 26 May 2023 by Mars2000you. Based on work by Gdx and Grauw and others.



This is an SD(HC) card interface with dual slots (one SD and one microSD). It is based on the open source hardware design created by Fabio Belavenuto, and the PCB was originally designed by MSXpro then modified by 8bit4ever to support the microSD form factor. Basically, it is the SD Mapper/Megaram 512kb a little redesigned.

The contacts of the EDGE connector are gold plated.

Price: About €60 including shipping costs for worldwide. This interface is also sold by several people for various prices.


Version 1

8bits4ever SD-512 - v.1
8bits4ever SD-512 + SD card - v.1
8bits4ever SD-512 back + SD card - v.1

Version 2

8bits4ever SD-512 - v.2
8bits4ever SD-512 PCB - v.2
8bits4ever SD-512 PCB back - v.2

Minimum Requirements

  • MSX1
  • 1 cartridge slot free (primary slot to use the RAM as MegaRAM or RAM expansion)

Attention! This cartridge is not compatible with the Mitsubishi ML-G1 and the Sanyo MPC-100 machines


  • 1 SD slot and 1 MicroSD slot (MicroSD up to 32GB)
    • FAT 12/16 partitions (up to 256MB in FAT12 and 4GB in FAT16)
  • Flash ROM: 512kB
  • RAM: 512kB
  • Support R800 ROM/DRAM mode on MSX turbo R and Panasonic MSX2+ turbo mode
  • 1 switch to disable the RAM (This allows the cartridge to be used in a secondary slot)
  • 1 switch to select the RAM configuration (MegaRAM or RAM expansion)

Note: The first version only supports SD cards up to 2GB and has no MegaRAM mode.


  • The Flash Rom is used for the Disk-ROM and its driver (Nextor)
  • The RAM can de used as RAM expansion or MegaRAM (Supported Rom mappers: ASCII, Konami, Plain Rom).


  • ExecROM - Rom loader
  • LOADROM - Rom loader
  • MI.COM - Mapper info by Yukke
  • MEGA16.COM - Megarom with ASC16 mapper loader
  • MEMTEST.COM - RAM of memory mapper tester by Masatoshi Fujimoto
  • Nextor (Driver is included in the SD-512 Disk-ROM)
  • ODO.COM - Rom loader
  • SDMUPD.COM - SD-512 updater (included software)
  • Sofarun - UI for DSK, MegaROM and ROM loader by Louthrax
  • SymbOS (Driver is included with SD-512 software)
  • TESTMAP.COM - Memory mapper RAM tester by Marteen