Felucca, custom firmware for the M-VAVE FM-1, and what stepping back means for users

Custom firmware for a specific hardware instrument, not a general synth

Felucca is firmware for one device: the M-VAVE FM-1. The README describes it as multi-engine synthesizer firmware for the FM-1, version 1.6.1, and the project is written in C. That constraint is the whole point, and it is the first thing to establish before reading further, because it decides who the audience is and what the software can possibly do.

The audience is a person who already owns an FM-1 and finds the stock firmware limiting. The alternative audiences are explicitly ruled out by the project's own framing. There is no host application, no plugin, no desktop editor binary, and no second supported instrument. The installation path is a browser talking to the hardware over USB, so the computer is a delivery mechanism rather than the place where the instrument lives.

The project also splits into four distinct pieces, and keeping them apart makes the whole easier to judge. This repository holds the firmware itself, with firmware/ and build.sh at the top level. Felucca-WebApp is the separate repository for the web editor that patches the instrument. Felucca-Engines holds the ANALOG, LOFI, TRIO, WHEEL and NOISE engines under an MIT licence, and the README notes that repository is still maintained. felucca-bsp is the FM-1 hardware layer. A .gitmodules file in the top level entries indicates these pieces are wired together as submodules, so the split is deliberate rather than accidental duplication.

The browser installer, the in-browser try-out, and the way back to stock firmware

The install story is short enough to state in one breath, and it is unusual enough to be worth stating carefully. The README says to connect the FM-1 to a computer by USB, open the web installer in Chrome or Edge, and press Install. No extra hardware is needed. That constraint on browser choice is explicit, so a Safari or Firefox workflow is not covered by the documentation.

The README also says installing is at your own risk, and that the M-VAVE updater, or the installer's own Return to official V15 option, takes you back to the original firmware. This is the single most important operational fact in the README for anyone about to press the button. The escape hatch is documented and there are two routes to it, which means the downside of trying the firmware is a revert rather than a bricked instrument, at least as the project describes it.

There is a second entry point for people who do not own the hardware. The README links a browser try-out page and states that no FM-1 is needed, which means the sound design and the editor interface can be evaluated before buying an instrument. That page is the cheapest possible evaluation path, and it also makes the editor a standalone tool for anyone who wants to design patches without owning the hardware.

A third surface is the web editor, kept in its own Felucca-WebApp repository, and the README points to a wiki that holds the manual and the release notes. The three release tags in the recent list, v1.5.1 on 2026-10-10, v1.6 on 2026-10-13 and v1.6.1 on 2026-10-14, show the project shipping versioned firmware rather than a continuously changing download.

Where the code actually lives, and how the build is arranged

The top level entries describe a real project rather than a script dump. Alongside the README and the licence files there is BUILDING.md, which the README names as the place to find build instructions, and a build.sh script at the root. There are directories for firmware, tools, tests, docs and web, plus assets, a .github directory, a .gitmodules file and per-contributor guidance in CONTRIBUTING.md.

The separation of firmware, web and tools mirrors the repository split described earlier. The web directory in this repository corresponds to the installer and try-out pages served from the project's GitHub Pages site, while the separate Felucca-WebApp repository holds the editor application. The engines live under firmware/engines, and the README states that the engines in firmware/engines are MIT licensed, drawn from Felucca-Engines.

Two things a reader should not expect to find in the README, because they are not there. There is no step by step command sequence for the build, no list of toolchain versions, and no note about a host operating system. Those details are what BUILDING.md and the wiki are for. Anyone planning to build from source needs to read BUILDING.md before assuming the build is a single command, and anyone planning to go beyond the released binaries needs to budget time for that reading.

The test directory is worth a note as well. Its presence says the project has a testing story, but the README does not say what the tests cover or how they are run, so it would be wrong to claim any particular coverage level.

The maintenance notice that changes the risk calculation

The README opens with a maintenance notice, and its content matters more than the repository's recent activity suggests. The author writes that what began as a personal experiment grew beyond expectations, thanks contributors and users, and that the decision is to step back from active development to focus on creating new instruments and music. The README says Felucca will remain available with occasional maintenance, but that new features, issue responses and pull request reviews are not guaranteed.

The release dates look busy. The last push was on 2026-10-22, and v1.6.1 was tagged on 2026-10-14, v1.6 on 2026-10-13 and v1.5.1 on 2026-10-10. Read together with the notice, that pattern reads as a release cadence that is winding down rather than a sign of ongoing development, and the notice is the authoritative statement about the project's future. A user who opens an issue should expect no response; a contributor who sends a pull request should expect no review.

The practical consequence is that the community responsibility has moved to the users. A feature you need, a bug you hit, or a compiler update that breaks the build is now your problem to solve, either by working in the repository yourself or by asking the still-maintained Felucca-Engines repository, which the README explicitly marks as still maintained. Forking is the natural path, and the GPL-3.0-only licence makes that legally straightforward, since a distributed derivative must keep the same licence and pass on the source. Nothing here is legal advice, but the licence and the maintenance notice point the same way.

Licence split across firmware, engines, samples and fonts

Felucca is a multi-licence project, and the README is unusually precise about the pieces. The firmware itself is free software under GPL-3.0-only, with the licence file at the repository root. The Hügelton Sample Pack is CC0 1.0, which places it in the public domain as far as copyright is concerned. The engines under firmware/engines are MIT, matching the separate Felucca-Engines repository. The bundled fonts and the ported DSP keep their own licences, and the README points to a LICENSES directory and a LICENSING.md file for the details, with CREDITS.md listing the people whose work is in the project.

That layering is worth understanding before you build anything on top. If you redistribute the firmware, the GPL obligations travel with it. If you take the sample pack on its own, CC0 1.0 means there is nothing to attribute for that material, though the README still credits it. If you extract the engines for use in your own work, they are MIT, which is a much lighter obligation than the GPL that governs the firmware as a whole. The ported DSP is the category to check most carefully, because the README says only that those components keep their own licences, which means you need to read LICENSES/ and LICENSING.md for the specifics rather than assuming the MIT terms cover them.

On branding, the README is clear: M-VAVE and FM-1 are trademarks of their respective owners, and Felucca is not affiliated with or endorsed by them. Copyright is held by Leo Kuroshita (@kurogedelic) and Hügelton Instruments for 2026.

Where Felucca is the wrong tool, and how the alternatives differ

Felucca is the wrong choice in several concrete situations. If you do not own an M-VAVE FM-1, it does nothing for you, though the browser try-out page lets you at least evaluate the design. If you need a general purpose synthesizer for composing, this is not a music production tool and the README does not describe export to a DAW or any file interchange. If you want ongoing upstream fixes, you are reading a notice that says they are not guaranteed.

The real alternative is the stock M-VAVE firmware, reached through the M-VAVE updater. The difference in approach is direct. The official firmware gives you the instrument as its manufacturer defined it, with a support path that belongs to the manufacturer, and it is what Return to official V15 restores. Felucca gives you multiple engines, including the MIT licensed ANALOG, LOFI, TRIO, WHEEL and NOISE set, in a browser-driven install, and it gives you the ability to modify and fork the source under the GPL. Choosing Felucca is choosing flexibility over a support relationship; choosing the stock firmware is choosing the opposite, and the README is candid enough to point at both.

A second alternative is the browser editor on its own, used with the hardware you already have, if you want the patch design experience without changing the firmware.

One more piece of context belongs here. The README states that Felucca is developed with the assistance of AI coding agents for code, tests, documentation, translation and maintenance, while the design, features, sound design and direction are the maintainer's or the community's, and that no generative AI is used for music, icons or artwork. A discussion thread on the subject is linked. For anyone with a policy on AI-assisted code in a dependency, that is a disclosure they can act on, and it applies to the Felucca repositories rather than being a general claim about the wider hardware ecosystem.

Editorial conclusion

Felucca suits an FM-1 owner who wants more than the stock instrument and is comfortable reading BUILDING.md and the wiki to build or modify firmware, and it suits a browser tester who wants to try the sound design before buying hardware. It does not suit anyone who needs new features, bug responses or pull request reviews, because the author states plainly that active development has stopped and only occasional maintenance will continue. Before you commit, verify that the engine you want is in firmware/engines or in the still-maintained Felucca-Engines repository, read the firmware/engines and LICENSES entries to see which code carries the MIT licence and which keeps its own terms, and keep the M-VAVE updater available, since Return to official V15 is the documented way back.

Frequently asked questions

Official sources

1. hugelton/Felucca on GitHub
2. Issues
3. License: GPL-3.0
4. README
5. Releases