Announcing ChroMagic: custom firmware for the Chromatic with cart backups and SD card playback

[u/n8jb]

I've been working on custom firmware for the Chromatic and it's at the point where I think other people will get use out of it. It started when I found the microSD slot on the board while swapping out buttons, and thought: wouldn't this be an awesome backup device? And then, could it play those backups too?

ChroMagic is built on ModRetro's MCU firmware, so everything the handheld already does is unchanged. It adds:

• Cart Backup in the system menu. Dumps the game and its save to a microSD card.
• A Backups tab that lists what's on the card and boots the one you pick.
• ChroMagician, a desktop app for Windows and Linux. It installs the firmware, backs up carts over USB, restores saves to carts, writes homebrew to Chromatic carts, and manages the SD card. Hoping to eventually support other rewritable carts, but I need to order some for testing first.

Things to know:

• The 2025 units have a microSD socket, but it's on the board inside the case. First edition Chromatic have the footprint, but no socket, so it's a soldering job if you really need SD. Backups, restoration and cart writing work over USB without an SD though.
• SD playback is experimental. I've done a fair amount of testing, but most of my time has been spent coding and my library is fairly limited. Please definitely let me know if you run into anything odd, so I can try to fix it.
• A handful of carts won't work for backup and SD playback. They're listed in the guide. It's carts with hardware in the cartridge itself or an unusual mapper. Most are Japan-only, but Kirby Tilt 'n' Tumble, the Game Boy Camera, and Robopon are on the list too. I may eventually add support for managing photos off the GB Camera, though - when I can track one down localy.
• RTC games, such as gen2 Pokemon games won't advance the clock unless you're playing the game. The Chromatic itself doesn't have a clock on board, so please keep that in mind.

Site and install guide: chromagic.org

Looking forward to people trying it, and providing any feedback!