A Polish hacker named Asie has managed to reverse-engineer and implement a fix to allow WonderSwan owners to browse the internet with the Japanese handheld in 2023 (as highlighted by the game developer Brandon Sheffield on Twitter).
Much like the Game Boy and its successors, the WonderSwan handheld (which was released exclusively in Japan in 1999) was marketed alongside a bunch of additional accessories that players could buy to enhance the core capabilities of the console. One of these was the MobileWonderGate.
This was a device that allowed the WonderSwan to go online via a connection to an NTT DoCoMo PDC cellular phone and could be used to download DLC for games or take advantage of a special service called "mopera" to surf the web.
The MobileWonderGate went on sale back in July 2000 but its online service was eventually discontinued just four years later in 2004 due to a lack of users.
Since then, decades have passed, but a few individuals have stepped up to create a bunch of workarounds to get the device back online, with one hacker named Trap15 releasing the open-source hardware emulator WonderFence in 2014 to let players access the internet on original hardware/emulators without requiring a DoCoMo phone. This managed to get the hardware connected to the internet but didn't manage to resurrect the original web browser itself. And so, this is where Asie decided to step in!
The Polish hacker recently announced on their blog post (published on August 19th), that they have managed to resurrect the original MobileWonderGate browser, which up until now had failed to load thanks to being unable to perform "a secret handshake" with a special server. Asie writes that they were able to do this after reverse-engineering the request, figuring out that it acts as an "URL allow/deny/login-required" server, and performing a simple reimplementation to always return “allow” for any URL.
You can read the original blog post here to find out how to get it all up and running if you want to try it out for yourself. According to the requirements, you'll need access to Linux, a serial port adapter, a MobileWonderGate cartridge, and the Bandai WonderSwan itself.