Mega-CD BIOS Loading for the Amstrad Mega PC and Sega TeraDrive

Nix McRetro // 24th August 2012 // Hacks, Sega, YouTube

EverDrive, is there anything you don’t do?

This solves one half of an experiment I’ve been thinking about: getting the Amstrad Mega PC or Sega TeraDrive to work with an external Mega-CD.

I had originally thought I would need an Action Replay or Datel CDX cartridge to provide the Mega-CD BIOS. The Mega EverDrive can run a Mega-CD BIOS from the cartridge slot instead, which makes the software side considerably easier.

The 2012 Mega EverDrive firmware even includes a dedicated CD BIOS mode and a Run CD function.

That does not magically attach a Mega-CD to either machine.

The Mega-CD hardware still has to be physically connected to the Mega Drive expansion signals inside the Mega PC or TeraDrive. The EverDrive only helps with the BIOS-loading side of the experiment.

Still, one problem solved before I’ve even created the next one.

Excellent!

Sources

Mega EverDrive user manual - period documentation for Mega-CD BIOS loading and the Run CD function.

AI-assisted revision: This post was reviewed and edited with OpenAI GPT-5.6 Sol on 29 September 2026 for fact-checking, sourcing, and editorial cleanup. Final editorial responsibility remains with the author.