Genesis Save Converter
Open a Genesis or Mega Drive save and download it for Gens, Kega Fusion and the Mega EverDrive, for RetroArch's Genesis Plus GX, for the Retrode or for MiSTer. The converter detects whether the file is byte-expanded, and with which filler, and rebuilds it in the shape the target expects.
Or drop them here. They are read on this device and never uploaded.
Which Genesis save formats does it convert?
Most Genesis battery saves are 8-bit SRAM wired to the odd bytes of the 16-bit bus. Tools disagree on what to put in the even bytes, which is why a save from one emulator can look empty in another.
| Format | Files | Used by |
|---|---|---|
| Expanded with 0x00 | .srm | Gens, Kega Fusion, Mega EverDrive |
| Expanded with 0xFF | .srm | RetroArch Genesis Plus GX, MegaSD older .SRM |
| Each byte doubled | .srm | Retrode cart reader |
| Plain bytes | .sav | MiSTer (padded to 64 KB), save editors |
| MegaSD BUP2 | .SRM (open only) | MegaSD newer firmware |
How to convert a Genesis save
Open your save
Drop the .srm or .sav. The shape is detected; if the guess is wrong, pick the shape yourself.
Check what was found
The converter names the format it found and lists the saves inside, with any problem it spotted in the file.
Pick the format you need
Press the button for the emulator or device you are moving the save to. The new file downloads straight away.
Copy it into place
Put the downloaded file where your emulator or device keeps its saves, using the name the game expects.
What does byte-expanded mean?
Byte-expanded means each save byte takes two bytes in the file. Gens and Kega Fusion put 0x00 in front of each byte. Genesis Plus GX starts its SRAM buffer as 0xFF and writes only the odd bytes, which leaves 0xFF in front. The Retrode writes each byte twice. MiSTer stores the bytes plainly.
EEPROM saves, used by a few games such as Wonder Boy in Monster World, are small and never expanded. They pass through unchanged.
Other save converters
- PS1 Save Converter: Memory cards (.mcr, .mcd, .srm), PSP and Vita .VMP, DexDrive .gme, PS3 .PSV and single saves.
- PS2 Save Converter: PCSX2 .ps2 cards, EMS .psu, Action Replay .max, CodeBreaker .cbs and PS3 .PSV.
- N64 Save Converter: EEPROM, SRAM, FlashRAM and Controller Pak saves, RetroArch .srm, EverDrive 64 and DexDrive .n64.
- GBA Save Converter: Raw .sav, RetroArch .srm, GameShark .sps and .gsv, Action Replay .xps, with resizing.
- DS Save Converter: Raw .sav, DeSmuME .dsv and Action Replay .duc / .dss, with trimming and padding.
- GameCube Save Converter: Single .gci, GameShark .gcs and MaxDrive .sav saves, and whole Dolphin .raw cards.
- Game Boy Save Converter: GB and GBC .sav and .srm, with the MBC3 real-time clock carried across.
- SNES Save Converter: .srm and .sav for emulators and flash carts, Retron 5 saves, resizing.
- Saturn Save Converter: Mednafen .bkr and .bcr, Beetle Saturn, Yabause and plain memory images, plus single .BUP saves.
- Dreamcast Save Converter: VMU images, Nexus .DCI saves and .VMS with .VMI pairs.
Frequently asked questions
Why does a MiSTer save not load in RetroArch?
MiSTer stores the save bytes plainly, while Genesis Plus GX reads them from the odd bytes of an expanded file. Convert to RetroArch Genesis Plus GX .srm and it loads.
Can it convert Sega CD saves?
No. Sega CD internal and cartridge backup memory (.brm) use their own format.
Is the MiSTer file bigger on purpose?
Yes. MiSTer pads Genesis saves to 64 KB with 0xFF. The converter cuts that padding off when it opens a MiSTer file and adds it back for the MiSTer output.