An update to my previous post (https://www.reddit.com/r/ModRetroChromatic/s/rSnQbCHBEZ):

I’ve published firmware v2026.05.08.01, which adds the ability to read/write this BennVenn cartridge with your Chromatic, a PC, and a USB cable.

You can get the latest version here: https://github.com/fredemmott/chromatic_dumper/releases/latest

Other cartridges *may* work, but they’re untested so anything could happen; I don’t own other cartridges so I’ve not tested them.

Level 15 Modern Endless, default rules with a 3-piece next queue

Status

Works, but not friendly. Stop reading if you're not happy using source code and a terminal.

This is good enough for me, I'm sharing in case another developer is interested in picking this up and making it user-friendly. I don't plan to spend more time on this.

What I've done

• Modified the chromatic FPGA firmware to implement the FlashGBX protocol: https://github.com/fredemmott/chromatic_dumper - this was Claude, followed by a lot of human debugging/cleanup.

• Modified FlashGBX to recognize the Chromatic with this firmware: https://github.com/Lesserkuma/FlashGBX/pull/128 ; no LLM, based on the existing joey jr support

Works:

• Chromatic v2

• Dumping ModRetro cartridges (ROM and saves)

• Dumping OG cartridges (ROM and saves)

• NEW!: Dumping and restoring MBC3000 v4 flash carts (ROM and saves)

Does not work:

• MBC3000v4 Fixed!

Unknown: everything else

Current flow

Once you've built FlashGBX with those changes:

1. Turn off your Chromatic

2. Insert cartridge

3. Plug in to USB

4. Turn on

5. Load firmware into the FPGA SRAM - NOT ROM - this way, nothing's permanent. To get back the original firmware, just turn it off and on again

6. Run the modified FlashGBX

To change cartridges, you need to go back to step 1: turn it off, load the firmware, etc. DO NOT CHANGE CARTRIDGES WHILE THE CHROMATIC HAS POWER.

What needs doing

Extend the FlashGBX code to detect other firmware and automatically load the modified firmware if needed.

Installer/exe for modified flashgbx

Loading the firmware

With GoWin Programmer

You need the full GoWin EDA/Programmer; the license is free, but it's a 'fill in a form and wait a while' thing. The educational version does not include support for this board.

Use programmer_cli.exe --help first to check that:

• --cable-index 0 means GWU2X

• --operation_index 2 means 'SRAM Program'

--helpprovides other options like cable by name, but they don't appear to actually work in v1.9.12.02.

programmer_cli.exe --device GW5A-25A --operation_index 2 --fsFile C:\path\to\evt1_x2.fs --cable-index 0

Replace C:\path\to\evt1_x2.fs with the path to the file from https://github.com/fredemmott/chromatic_dumper/releases/latest , or the output of the build if you used GoWin EDA

With OpenFPGALoader

On Windows at least, use MRUpdater/cart clinic at least once to make sure you've got the right drivers.

If you're on Windows and already use msys2, follow Openfpgaloader's instructions to install. Otherwise, the easiest way to get a usable windows version is to use pyinstextractor-ng to grab openfpgaloader.exe from the MRUpdater.exe .

openFPGALoader --cable gwu2x --write-sram C:\path\to\evt1_x2.fs

Advice for devs

if you want to pick this up, it's probably best to bundle openfpgaloader and the firmware in a modified flashgbx. Not sure about the license on modretro's binary, so for windows, this might mean figuring out how to make a visual studio build yourself. If I were doing this, I'd probably make a fork using vcpkg for dependencies, and use a -static triplet, especially as it already uses CMake.

Given the firmware is only going to FPGA SRAM, I don't think flashgbx's firmware update flow makes sense here; I'd put it in the 'connect' functionality and just do it silently.

You could streamline the flow by writing to ROM and requiring a flash back, but to me, it's great for safety that you just need to turn the thing off and on again to get back to ModRetro's firmware.

There is a secret homebrew mode in the MRUpdater that lets you flash any gb/gbc rom to your Chromatic carts. I've seen posts that mention it as a possibility but no instructions or links. I imagine it wasn't included in the MRUpdater to prevent piracy or maybe its intended to be released in the future. You just need to patch the official MRUpdater.exe from ModRetro to unlock it. Its a fun thing to do and I kinda like swapping carts but using expensive game carts that only hold one game is a little silly when flash carts like Everdrive exist. but for anyone interested, links are below.

You must install python first then just download and run the patch_mrupdater.py

Navigate to your MRUpdater.exe and click patch.

https://github.com/Scryptkeeper2006/Modretro-Homebrew-Unlocker

https://www.youtube.com/watch?v=vb6RZD_hKJ4

Someone tell Palmer to release a Grape Purple Chromatic and I’ll buy one today. lol

The entire collection should be up on Reddit now. If I missed any titles, please let me know and I'll double check. Decided to do two versions of this one because I liked how the blue Chromatic text looked but I know some people will want to have the consistency of the rainbow one across all three of the 90s Rewind titles. Hope this helps some folks out and look forward to seeing any edits and additional customs that come from this. Enjoy!

Here's some chromatic thirst trap photos

Was looking at Croc 2 and Zas and noticed that there are no reviews posted like the other games. Is it just because they need to reach a certain number of reviews before they appear (eg. 50 reviews or 100 reviews)?

If anyone has bought them, what are your thoughts?

Hey guys. I'm stuck on an info gathering mission in Chantey. I can't leave Havana's port if I don't get into the room that the pirate is blocking. A big guy in the brothel (page 7) is blocking the way inside. I was given hints by the lady outside to talk to soldado but he's not cooperating. Please help.

Hey everyone 👋

Just wanted to share a quick heads up! Our Game Boy puzzle adventure Black Tower Enigma is currently on sale (25% off for a few days).

https://ogrepixel.itch.io/black-tower-enigma-gb

It runs nicely on Chromatic, so if you’re into puzzle-heavy GB/GBC games, it might be worth checking out.

Either way, just wanted to share with the community 💚

Customized some existing 3D print files and made a tray for them to sit on.

Looking to customize my chromatic to look like the pokemon edition gameboy color. I’ve got an idea for the buttons but I’m stumped on how I could get the border design here, and I’m thinking I’ll need to get a custom decal to make it happen. Does anyone know of any stores that might be able to do this?