TMMN Interviews RockmanCosmo on Preserving Mega Man Feature Phone Games

Who are you? Tell us a bit about yourself.

To put simply, I’m a Mega Man mega fan who works to preserve its history! I am the leader of SciLab Secrets, the team that’s working to preserve three lost Mega Man feature phone games. I have also been the leader of a few Mega Man English scanlation projects, most notably the scanlation of the Rockman DASH Great Adventure Guide.

I formally joined the online Mega Man community in 2020 to promote my LEGO Flutter project. After seeing poor-quality scans of the Great Adventure Guide, I decided to buy my own copy, scan it, and assemble a team to translate the whole thing into English. This was my first foray into Mega Man preservation, and in July 2022, we accomplished that goal!

How did you get involved in the preservation of mobile phone games?

I had been aware of the Rockman mobile phone games for a while, but since nobody could get their hands on a copy, I didn’t think much of them other than being neat spin-offs. However, that all changed in December 2020, when Protodude replied and retweeted a now-deleted tweet that showcased Rockman.EXE Phantom of Network on a flip phone.

This tweet piqued my interest, and I did some research on the phone model, DMing Protodude with my findings. Next, he added me to a tiny Twitter group chat, which was the start of the Rockman feature phone preservation project! My initial role was recruiting skilled programmers and researching device manuals. As Protodude became busy with other commitments, I gradually took on a leadership role, synthesizing our team’s progress in Rockman Corner update posts.

I became involved in preserving Japanese feature phone games in general in the Summer of 2021. I learned that the i-mode website, a site that hosted storefronts to purchase these phone games, was shutting down in November. I was shocked to learn this, and I was even more shocked that very few people were raising awareness about these games’ impending fate. I wrote an open letter to game preservation organizations in October, leading the Tokyo-based Game Preservation Society to download 876 games before the website’s shutdown on November 30th.

Ever since, I’ve done everything in my power to raise awareness about Japanese feature phone game preservation, from writing articles to appearing on podcasts.

There have been a number of Rockman games for mobile devices? Are you focusing only on specific ones?

Yeah, there were a surprising amount of Rockman games released for Japanese mobile phones. Capcom was a big supporter of mobile gaming back then! There were ports of the classic NES and even a port of Rockman X4 (split into two apps for X and Zero’s campaigns). There were also some interesting sports spin-offs like Rockman Tennis and Rockman DASH Golf.

Most notably, Capcom released original entries in the Rockman DASH and Rockman.EXE series, being Rockman DASH: Great Adventure on 5 Islands, Rockman.EXE Phantom of Network, and Rockman.EXE Legend of Network. By incredible strokes of luck, our team secured complete copies of all three games.

Since these are the only lost Rockman mobile games in our possession, our project is focused on preserving them in particular.

Why is each of these games important? That is, beyond the inherent importance of video game preservation, what about these games is important to fans of Mega Man Legends and Mega Man Battle Network?

Starting with 5 Islands, this game takes place between Mega Man Legends and Mega Man Legends 2, so it is canon! Volnutt and his crew travel to five different islands, each having different locales and missions. On Ilks Island (the third island), Denise Marmalade has a starring role, returning from The Misadventures of Tron Bonne! This has been her only other appearance in the series.

NetNavi images via MMKB.

Phantom of Network and Legend of Network feature original stories, characters, and NetNavis. They’re practically their own mini-entries in the greater Rockman.EXE series! Phantom of Network’s story focuses on cache data resurrecting past bosses. Its characters were even adapted into the final season of the Rockman.EXE anime. Legend of Network’s story has Lan and company fighting remnants of an ancient civilization with advanced net technology. It introduces a new mechanic, the Trans Arm, which functions similar to a Double Soul. Remarkably, both games play nearly identically to their Game Boy Advance counterparts. The battle system is unchanged, even including Program Advances! The developers only had to sacrifice an overworld and the isometric angle for Cyberworld segments.

How will people be able to Axess — er, access and play these games when the time comes?

As of the time of this writing, there is no reliable way to emulate DoCoMo Java (DoJa) games, which is what our copy of the Rockman mobile games run on. There is a rudimentary emulator embedded in the DoJa 5.1 SDK, but not all games work well with it.

However, team member Xer is actively working on an all-inclusive emulator for Java Micro Edition games, SquirrelJME. This emulator, when completed, will support DoJa games.

Our team will decide on how to distribute the games at a later time. Right now, our primary focus is finding a way to preserve their files.

Seeing as most (all?) of these games are in Japanese, are there any efforts in place to translate them? Is that something your group is looking at doing, or are you leaving that to others?

Yes! A few kind users have offered to help us translate the games. We will discuss translation work after our team finds a way to preserve the game files. A translation patch depends on if the game’s code is obfuscated or not.

With regards to localization, we’ve seen your collaboration to dub 5 Islands into English on YouTube. Any plans for a version of the game to contain this?

Unfortunately, I’m doubtful that the game (if it can even be modded) could handle such a large amount of audio. We have not decrypted 5 Islands’ game files yet, so I cannot say anything for certain regarding its modding potential.

How were you able to acquire these games?

Basically, we got super lucky. For the EXE games, a very gracious Japanese user loaned his phone to us so we could preserve the games on it.

Our copy of 5 Islands was donated to us by Midori, a longtime member of the Mega Man community. She owned it on a Japanese mobile phone, and moved the game to a microSD before she returned to the US. After losing the phone for years, she found it and kindly donated it to our team.

As you can see, none of this would have been possible if it were not for these benevolent people! We are endlessly grateful for their contributions.

How far along is each title?

The EXE games are gradually moving along. It’s been incredibly difficult to hack into their phone, because the phone model uses proprietary chips. We’ve spent a lot of time researching the phone models’ interiors, including desoldering the NAND chip and attempting to dump it, although that has ended in failure so far. This is likely due to its proprietary nature, but we’re working on finding a way to read it.

But do not fret, for there are a multitude of potential software exploits, from a NetFront browser exploit to a PDF reader exploit. As such, even if one avenue of attack fails for the EXE phone, we’ve got many other ways to hack into the phone to read its filesystem. This goes for all other phone models as well.

In recent months, 5 Islands has seen the biggest jump in progress. Unlike the EXE games, its files were moved onto a microSD card. However, these files are encrypted by a powerful DRM protection, CPRM. Other lost Japanese feature phone games also have their files encrypted on SD cards, and this encryption has never been cracked before.

But there is hope! Last month, team member GoodTofuFriday bruteforced a phone’s device key, which is one major piece of the CPRM puzzle. As of this writing, we’re actively working on obtaining the other puzzles pieces to finally decrypt 5 Island’s game files. It’s important to note that we have no idea what these decrypted game files look like, so there is a possibility that they’re fragmented or unplayable. There’s only one way to find out!

Many Mega Man fans may be wondering why it’s taking us this long to save these games. The answer is twofold.

Firstly, all of our team’s labor is voluntary, meaning that everyone is working out of the goodness of their heart and not for money. It’s a side project for everyone, driven by a passion for game preservation and the games themselves.

Secondly, we’re pioneers in this field of game preservation; we are attempting to do something nobody has done before. Nobody has ever extracted a game from the EXE games’ phone model, and nobody has ever decrypted a DoCoMo game dump from an SD card. Every challenge is a new challenge, but we aren’t giving up anytime soon. In fact, I plan on writing a more extensive update on Rockman Corner in the near future, so stay tuned for that!

Outside of the Mega Man games, are there other titles you’re looking at preserving?

The progress our team makes on our set of games benefits the preservation of other Japanese feature phone games, especially those that are encrypted on SD cards like 5 Islands. For example, Kingdom Hearts Coded, a Kingdom Hearts game released for mobile phones, was moved to an SD card from its phone. Our progress with cracking the SD’s CPRM will directly affect the preservation of that game too.

Therefore, while our team’s focus may not be on those other titles, our team members are active in the greater Japanese feature phone game preservation community and help assist with preserving other games. It’s a team effort that spans the globe!

Are you looking for further help with preserving these titles?

The only specific help we’d need at the moment is someone who’s knowledgeable in NetFront Browser exploits. This browser has been exploited in NDS, 3DS, and PSPs, and the NetFront browser used in our phone is even older than those. There is an extremely high chance we can exploit it; we just need someone knowledgeable to give us pointers.

If you’re interested in helping, I can be reached through my website, by email at rockmancosmo (at) gmail.com, or via Twitter @RockmanCosmo.

Thanks for taking the time to chat with us about the project. We wish you the best of luck, and look forward to future developments!

Thanks! I appreciate TMMN giving me the opportunity to come on and speak about this project.

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Unless stated otherwise, images for this article were provided by RockmanCosmo.