ElkSD64 SD Card Interface & RAM Expansion

Praise for the ElkSD64

"A must own" - Chinnyvision (Youtube)
"It's hard not to recommend the ElkSD64" - Least Significant Byte (Youtube)

ElkSD64 Features

  • Uses standard SD cards, up to 8GB in capacity
  • Connects directly to the Electron's expansion port
  • Expands the Electron to 64K of RAM
  • Excellent compatibility with games (PAGE=&E00)
  • Uses widely available .SSD disk image files
  • 3D printed protective case
  • Free sidways RAM page can be used to load ROM images
  • LOAD and SAVE your own programs
  • Uses the popular MMFS filesystem
  • The most popular Electron memory card inter​face!

About the ElkSD64

This is the Electron memory card board that gets as close as possible to my ideal design, at least within the constraint of still being reasonably priced. My earlier boards were intended as inexpensive, easy and quick ways to make use of memory cards on the Elk.

I feel they did that job well, but there was clearly a need for a more advanced interface with more features and increased compatibility. Since before the Mk1 went on sale I'd been working on how to bring such a design to fruition without costing silly money. The ElkSD64 is the result of that process. It takes the proven ElkSD32 design and adds 32K of sideways RAM, the flash memory is now user-programmable, and the standard MMFS software is replaced by the 'Z' version which runs from sideways RAM. 

The 3D printed case of the ElkSD32 is retained, with the colour changing to white (ivory white on early models, pure white on later ones) with the design slightly modified to make removing the interface a little easier.

There are four 16K sideways banks available on the ElkSD64, two flash and two RAM. By default MMFS is stored in the first flash bank, at boot up it copies itself into a sideways RAM slot and runs from there. This means none of the Electron's main memory is used, permitting games that require PAGE to be set to &E00 - which wouldn't run on my earlier interface cards - to work correctly. 

The remaining two sideways banks, one flash and one RAM, are available to the user. ROM images can be loaded into either slot, and there are some games that will use the extra RAM.


The ElkSD64 has received positive reviews from a wide variety of retro computing channels on Youtube. These are a selection of the best and most informative reviews.

Buying an ElkSD64

The ElkSD64 is available to buy via EBay UK. Click the logo to fisit the product page.


User Guide ESD_Guide.pdf ElkSD64 full user guide.
Installation Instructions elk64_inst.pdf Installation Instructions
Games Collection (Small)
elksd.zip A small curated colleciton of Electron games, runs from SD card on all Electrons.
Games Collection (Big) elkbig.zip A large third-party collection of Electron games, some need sideways ram to run.
MMFS Update updater.zip Updates older ElkSD64s to MMFS 1.43.
Check README Before Using
ElkSD64 flash tools util flashtools.zip  Utility to flash the ElkSD64 sideways flash ROM.