Games & Preservation

Backing Up Sega Genesis Games

The Genesis (Mega Drive outside North America) shares its best dumping hardware with the SNES — if you own a reader for one, you already own it for both. Genesis cartridges are straightforward, mostly mapper-free, and dump in seconds. The ground rules apply as ever: own it, dump it yourself, keep it private.

Media
Genesis / Mega Drive cartridge.
Hardware
Retrode 2 (native slot), Open Source Cartridge Reader, or INLretro.
Output
.md (also seen as .gen / .bin — same raw data).
Typical size
512 KB – 4 MB.
Save data
Battery-backed SRAM/FRAM in a minority of carts (Phantasy Star IV, Sonic 3) — dump those first.
A Sega Genesis Model 2 console with six-button controller
The Sega Genesis (Model 2) with the six-button controller. Its cartridges are among the simplest of the era to dump. Image: Evan-Amos, CC BY-SA 3.0, via Wikimedia Commons.

What You Need

Dumping, Step by Step

ROMSRAM(SRAM in some carts)Genesis cartridge1Retrode / OSCRcart mounts as USB drive,or dumps to microSD2Game.md+ save file512 KB – 4 MB3OWL media libraryplays in the browser — save states synced
The Genesis dump: (1) a simple board — ROM, plus battery-backed SRAM in the games that save, (2) read over USB or to microSD, (3) yielding a .md file and, where applicable, its save. Diagram: NDEVR.
  1. Clean the edge connector with isopropyl alcohol.
  2. Insert and copy. Retrode: drag the ROM and save off the mounted drive. OSCR: choose Mega Drive and it dumps both to the card.
  3. Save first, ROM second for the battery-backed titles below.
  4. Verify. Dump twice and compare, or check the checksum against the No-Intro database.
★

.md, .gen, .bin — and the odd one out

Genesis ROMs travel under three extensions for the same raw bytes; .md is the modern convention. The one to avoid is .smd — an interleaved format from 1990s copier hardware. Modern dumpers write the raw format natively, so you’ll only meet .smd in very old dumps.

Battery Saves

Most Genesis games used passwords, but the ones that save — Phantasy Star IV, Shining Force, Sonic 3 (& Knuckles), Story of Thor — mostly keep it in battery-backed SRAM, now 30+ years old. Dump those saves before anything else; the readers above can restore them to the cartridge after a battery swap. (Sonic 3 is a happy exception — its FRAM keeps data without any battery.)

Playing Your Backup

Upload Game.md to your OWL media library and the Games collection runs it in the browser on the player’s Genesis core — box art, per-console settings, save states synced across devices, and Play Together for handing a friend the second controller. Your library lives in your own end-to-end encrypted storage.