Please avoid buying bootleg cartridges. Doing so encourages not homebrew development, but copyright infringement. Their hardware details are listed for people who ended up with bootleg cartridges already, as well as for documenting the history of the WonderSwan aftermarket hardware scene.

There is reason to believe that more non-bootleg reflashable cartridge solutions may be available soon. Please stay patient.

Note that any photos or videos provided here, unless otherwise specified, are not licensed under the same Creative Commons terms as the wiki. Please ask their author for permission.

Notes:

• “Re-flashable?” terms:
  • “Self” - the WonderSwan alone is sufficient to flash the cartridge. One can use BootFriend to reflash such a cartridge.
    • Be careful - if the cartridge is re-flashed without a valid cartridge header, the console will not turn on with it inserted again!
  • “USB” - the cartridge includes a USB port which can be used for flashing.
  • “External” - external device required. This does not include hardware which has an edge connector or pinout for manufacturing use only, or ones which can only be flashed through an external WS-compatible dumper.
  • “?” - not fully tested, most likely it is “Self” that is unknown.
• Cartridges marked in Bold are currently manufactured (as of writing).

Photo	Name	Flash chip	PCB marks	Flash size	Re-flashable?	SRAM Size	RTC	Mapper	Notes
	Wonderswan 8MB, 32KB FRAM Flash Cart (InsideGadgets)	MX29LV640ET/EB		8 MB	External	32 KB	No	2001
	WS Flash Masta	JS28F00AM29EWHA	WS Flash Masta USB	16 x 8 MB	USB, Self	512 KB	?	2003 (or compatible)
	WonderMagic Color	?		4 MB	External, ?	32 KB	?	?	The only console-contemporary flash cartridge. Rare.
	WonderDog V1 (64Mbit)	?		8 MB	External, ?	32 KB	?	?
	WonderDog V3 (64Mbit)	?		8 MB	External, ?	256 KB	?	?
	WonderDog V3 (32Mbit)	M29W320CT	PTS-0101	4 MB	External, ?	256 KB	?	?
	WonderDog V3 (4Mbit)	MBM29DL400TC	PTS-0101	512 KB	External, Self	256 KB	?	?	WonderWitch clone
	(Bootleg) AliExpress/liulili_0421	MX29LV640???	WONDERSWAN REPROGRAM CARTRIDGE DESIGN BY LIULILI_0421	8 MB	?	256 KB	?	?
	(Bootleg) AliExpress/Judgment Silversword	S29GL064A90TFIR4	-	8 MB		256 KB	?	2003
	(Bootleg) Shopee/Judgment Silversword	MX29LV640EB	674162A-Y23-211129	8 MB		256 KB	?	2003	Stolen from up-n-atom's WonderWitch design, but incompatible with WonderWitch
	(Official) WonderWitch	MBM29DL400TC	PTS-0101	512 KB	Self	256 KB	Yes	2003	Added for completeness.

Photo credits:

• WonderMagic Color: up-n-atom
• WonderDog V1/V3: ayasuke2

• The “Due to hardware limitations” compatibility list is outdated and inaccurate. Software flaws in the official menu software caused many of the incompatibilities.
• Flash Masta rev4 uses a genuine Bandai 2003 chip, rev5 uses a re-implementation - details unknown.
• Until August 2023, the price was $100 (with the occasional 10-20% off sale).
• The SD card port available on the Flash Masta rev4 is non-functional - it's wired up to the AVR chip, but there is no way exposed to use it on production firmware.

• WS Flash Masta flashing software
• CartFriend unofficial WS-side menu software - highly recommended

• The GBxCart with an edge adapter is required to flash this cartridge.

• Product page - contains flashing and save management software

• WonderMagic Color flashing software