WonderWitch - WonderSwan Development Flash Cartridge
WonderWitch - WonderSwan Development Flash Cartridge
⚠️ Important Notice
Only development version games and programs can be flashed — genuine commercial game ROMs cannot be burned to this cartridge. This is a developer tool for WonderWitch-compatible homebrew and open-source software only.
What is it?
The WonderWitch Flash Cartridge is a handmade development cartridge for the Bandai WonderSwan / WonderSwan Color handheld, compatible with the original WonderWitch development platform. It allows you to upload, download, and run WonderWitch development programs directly on real WonderSwan hardware.
The package includes:
- ➡️ Handmade WonderWitch flash cartridge (chip salvaged from original cartridge)
- ➡️ HDMI connector data transmission board (USB Type-C to WonderSwan link)
WonderSwan / WonderSwan Color console not included — shown for demonstration only.
Connection Method
Computer → USB-C Transmission Board → WonderSwan (with WonderWitch cartridge inserted)
- Insert the WonderWitch flash cartridge into your WS or WSC
- Connect the transmission board via USB-C to your computer
- Open the WonderWitch client software, select the recognized COM port
- On the WonderSwan, select Communication to connect to the computer
- Upload or download development programs freely
Note: Currently only confirmed working on Windows 10. Windows 7 compatibility untested.
What Makes It Special?
- Rare developer tool: Original WonderWitch transmission cables cost hundreds of dollars and are extremely scarce — complete sets with cartridge sell for thousands
- Handmade with original chips: Chip salvaged and repurposed from original WonderWitch cartridge hardware
- WS & WSC compatible: Works on both WonderSwan and WonderSwan Color (WSC-exclusive color games require WSC hardware)
- Low power optimized: Iterated through many versions to achieve low battery consumption matching the original
- Active homebrew ecosystem: WonderWitch official website (wwgp.qute.co.jp) still accessible — client software and 2001–2003 open development works available for download
Technical Notes
- Available user space after system: less than 400KB
- Supported game size: 64KB – 300+KB
- File directory stored in SRAM — battery required at all times (removing battery clears stored programs on next boot, same behavior as original hardware)
- WonderSwan Color games cannot run on original WonderSwan (same as GB/GBC compatibility)
- Some WSC games display in black & white on WS (e.g. Tetris, Immortal World 2)
Tested Compatible Games
- Dice Knight (notably different from the retail version)
- Silver Sword of Judgment — Mission Edition
- Various small WonderWitch homebrew games