WonderSwan bootrom dumped 20 years after release

WonderSwan.jpg

On the 4th of March 1999, Bandai released the WonderSwan in Japan. It had been developed and supervised by Gunpei Yokoi up until his tragic death in 1997, and was set to compete with the other console that he designed earlier while working at Nintendo, the Game Boy. Sadly, the WonderSwan turned to be a commercial failure, only managing to obtain a small portion of the Japanese handheld market before being completely crushed by the Game Boy Advance later on, without ever seeing an official release overseas. However, its memory still lives on in many enthusiast's hearts, whether it is in appreciation of the legendary game designer's legacy or due to its niche yet quality games.

20 years after release, a breakthrough has been made by furrtek in an effort aimed towards game preservation and better emulation: the WonnderSwan's bootrom has finally been dumped. This has been possible thanks to a hardware-based attack which glitches the CPU to trick the console into booting up without clearing the memory region containing the bootrom; a method very similar to the one used years earlier with the Game Boy Color. Still, the journey wasn't an easy one, as it was filled with many non-trivial platform-specific hurdles: for example, the original approach overclocks the CPU repeatedly and in short bursts to make it skip the memory clearing instruction, however, the WonderSwan's CPU has a much higher frequency tolerance than the Game Boy's. Nevertheless, thanks to an FPGA, custom code, experience and a lot of patience, furrtek has managed to dump both the original model and the WonderSwan Color's bootroms, and everything has been documented in a post linked in the sources below! (in French)

Now, you may be asking yourself: "This is cool and all, but what does this mean for me as a retrogamer aside from seeing a fancy boot screen?". byuu, the creator of bsnes and higan, has stepped forward to answer the question: the WonderSwan's bootrom also contains a settings menu which lets a player store his/her own personal info such as the name, birthday, gender and blood type. This data can later be used by games to do all sorts of things, like triggering easter eggs or automatically filling a character's name with your own. Now that the bootrom has been dumped, this feature can finally be configured and emulated properly!

byuu's post (NOTE: the WonderSwan Color's bootrom has since been dumped) said:
Courtesy of furrtek, we now have the WonderSwan boot ROM extracted and emulated! furrtek was able to achieve this via clock glitching the original hardware during boot-up and then extracting the ROM via serial. WonderSwan Color is next up.

The reason this is important is not just the boot screen logo. If you hold down the start button during startup, the WonderSwan boots into a settings menu where you can configure your name, birth date, gender, and blood type. For the last one, remember this is Japan. In Japan, blood types are roughly analogous to the west and horoscopes.

Your settings are stored on an internal EEPROM (memory chip), which WonderSwan games can then read back to customize the game for you: pre-filling in your name, providing easter eggs, etc. Some cartridges further provide a real-time clock, which can trigger events on your birthday.

With the boot ROM now dumped and emulated, these settings can now be configured via emulation.

Starting from version 106.197, Higan has implemented support for the newly dumped bootroms. You can see a video of it in action below:


If you want to try it yourself, you can download Higan's latest nightly builds here. WonderSwan bootrom dumps contain copyrighted content and cannot be linked to on GBAtemp, so you will need to obtain one yourself (hashes for verification can be found here).

:arrow: Source 1 (furrtek's post)
:arrow: Source 2 (byuu's blog)
 

Daggot

Well-Known Member
Member
Joined
Aug 3, 2015
Messages
689
Trophies
0
XP
1,964
Country
United States
shame how the WS got crushed there was a digimon game exclusive to it iirc if the WS had a western release wonder if we would've seen a official localization
There was also an exclusive Megaman Battle Network game(it was a platformer interestingly enough).
 

AlterL

Active Member
Newcomer
Joined
Aug 12, 2019
Messages
40
Trophies
0
Age
25
XP
124
Country
Venezuela
does anybody knows how to play games from this console with a 3ds? or how to make dualswan work? maybe a cia from nomadswan
 

Taleweaver

Storywriter
Member
Joined
Dec 23, 2009
Messages
8,286
Trophies
1
Age
41
Location
Belgium
XP
6,838
Country
Belgium
This has been possible thanks to a hardware-based attack which glitches the CPU to trick the console into booting up without clearing the memory region containing the bootrom
Of course! Why didn't I think of this? :)


...

probably because I don't have a clue what that actually means.
 

wormdood

pirate booty inspector
Member
Joined
Jan 3, 2014
Messages
5,191
Trophies
1
Age
36
Location
behind a parental advisory sticker
XP
3,729
Country
United States
Never used the system, but the button placement on this thing looks really wierd.
that's because some games used the same button layout as the original gameboy (d-pad a b start and select) and they were played on the console horizontally and there were also some other games that used the d-pad and four face buttons and they played vertically
 
General chit-chat
Help Users
    KenniesNewName @ KenniesNewName: Excited about adding a 4tb drive into my og Xbox for a beastly aio classic machine