# Felucca licensing Felucca is free software, licensed under the GNU General Public License, version 3 only (`GPL-3.0-only`, full text in `LICENSE`). That covers the code and its own assets. A few bundled or ported parts keep their own licences; they are listed below, and their licence texts are in `LICENSES/`. Copyright (C) 2026 Leo Kuroshita (@kurogedelic), Hügelton Instruments Copyright (C) 2026 Juan Ignacio Antonucci (Juan Jiant) — JIANT FM, the fork of Felucca in this tree: its own files and its modifications. A file's header says which: "Copyright (C) 2026 Juan Ignacio Antonucci (Juan Jiant)" where the file is mostly JIANT's, "Portions Copyright (C) 2026 Juan Ignacio Antonucci (Juan Jiant)" where it is mostly Felucca's and JIANT changed it; Felucca's line stays wherever it was. The licence is the same: GPL-3.0-only. ## What is GPL-3.0-only Every file in this tree that carries an `SPDX-License-Identifier: GPL-3.0-only` header: - the firmware: `firmware/` (app, HAL, update loader) - the build script and tools: `build.sh`, `tools/` - the web pages (installer, editor, the browser emulator `web/emu/`) and their tests: `web/` (not the Fukiai and DotGothic16 fonts, below) - the host tests: `tests/` - JIANT FM's interface art: `assets/ui-art/`, `assets/ui-shapes/` and the concept image `docs/jiant-fm-ui-concept.jpg` (by JIANT's author, under GPL-3.0-only like the rest of JIANT) - the JIANT FM plugin for tuttidaw: `web/plugin/` (below) One source file is a port and keeps the licence of its original: `firmware/src/fm6_core.c` (msfa, Apache-2.0). The firmware built with it is GPL-3.0-only as a whole. (The PHYS engine, ported from DaisySP and Rings, MIT, was removed in FELUCCA TONIC.) You may use, study, change and share Felucca under the GPL. If you distribute Felucca, or firmware derived from it, you must also give your recipients its complete corresponding source under the same licence. That includes devices that ship with modified Felucca inside. ## The JIANT FM plugin for tuttidaw (weavejam) `web/plugin/` (the headless renderer, the part stems, the fractional tempo, the plugin page and its protocol, the site's build) and the `JIANT_TUTTI` parts of the firmware it needs are by weavejam, in the fork , under GPL-3.0-only like the rest of JIANT: Copyright (C) 2026 weavejam It is weavejam's plugin build of JIANT FM by Juan Ignacio Antonucci (Juan Jiant), : JIANT FM (all of its sound and the instrument), built for the browser as `web/emu/` is; everything above and below applies to it. It is not affiliated with or endorsed by M-VAVE or Hügelton Instruments. Its site (`web/plugin/build.sh`) serves the licence texts, `LICENSING.md` and the README's credits with it (`/licenses/`), names its source (the commit it was built from) on `/credits.html`, and says that it is not affiliated with or endorsed by M-VAVE or Hügelton Instruments. tuttidaw only talks to it at arm's length (a sandboxed frame of another site, messages): tuttidaw is not part of it and does not become GPL by hosting it. ## Hügelton Instruments' own work All by Hügelton Instruments (Leo Kuroshita), in this tree: | What | Licence | Where | | --- | --- | --- | | Felucca: firmware, tools, web pages, tests | GPL-3.0-only | `LICENSE` | | The PHASE engine's waveforms: a C port of the oscillator of CrispyZebra () | GPL-3.0 | `firmware/src/eng_phase.c` | | The DRUM voices and kit | GPL-3.0-only | `firmware/src/drum_voice.c`, `firmware/src/eng_drum.c` | | The Hügelton Sample Pack: Felucca's drum sounds, made by `tools/gen_waves.py` (not CC0; JIANT builds none of them in: SLICE, which played its BREAK, is retired) | GPL-3.0-only | `tools/gen_waves.py` | | The Fukiai icon font (): the firmware's icons (rasterised at build time by `tools/gen_aa_icons.py`) and the web editor's | MIT | `web/fukiai.ttf`, `LICENSES/MIT-Fukiai.txt`, `web/FUKIAI-LICENSE.txt` | | fm1-clk320-probe by curist (): the switch from the FM-1's 360 MHz to JieLi's rated 320 MHz behind MENU > SYSTEM > CPU CLOCK (JIANT 0.9.12; the check of the clock registers and the switch), unchanged; its sequence after the JieLi AC79 SDK's `sys_clock_update` (Apache-2.0) | MIT | `firmware/hal/fm1_clk320.h`, `LICENSES/MIT-fm1-clk320.txt` | ## Third-party material | What | Licence | Where | | --- | --- | --- | | IBM Plex Mono (SemiBold) by IBM Corp. and Michroma by The Michroma Project Authors: the UI's values and big titles since JIANT 0.6.56, rasterised into the firmware at build time (`tools/gen_aa_font.py --preset jiant-lab`; the generated tables are not offered as a font) | SIL OFL 1.1 | `assets/fonts/IBMPlexMono-SemiBold.ttf`, `assets/fonts/Michroma-Regular.ttf`, `LICENSES/OFL-IBMPlexMono.txt`, `LICENSES/OFL-Michroma.txt` | | Chakra Petch font by The Chakra Petch Project Authors: the UI text since JIANT 0.5 (the labels since 0.6.56), rasterised into the firmware at build time (`tools/gen_aa_font.py --preset chakra-petch`; the generated tables are not offered as a font) | SIL OFL 1.1 | `assets/fonts/ChakraPetch-*.ttf`, `LICENSES/OFL-ChakraPetch.txt` (also `assets/fonts/OFL-ChakraPetch.txt`) | | Inter Tight font by The Inter Project Authors: the UI text up to JIANT 0.4 (kept for the `inter-tight` preset; the font declares no Reserved Font Name) | SIL OFL 1.1 | `assets/fonts/InterTight[wght].ttf`, `LICENSES/OFL-InterTight.txt` (also `assets/fonts/OFL.txt`) | | msfa by Google Inc. and Pascal Gauthier, from Dexed (): the FM6 engine's synthesis, ported to integer C (Dexed itself is GPL-3.0; only msfa is used; the FM6 factory patches are Felucca's own) | Apache-2.0 | `firmware/src/fm6_core.c`, `LICENSES/Apache-2.0-msfa.txt` | | klattsch by Tony Gies (): design reference for the VOICE engine; no code copied. Formant data from Klatt (1980) / Hillenbrand et al. (1995) | MIT (klattsch) | credit only | | The CMU Pronouncing Dictionary (cmudict 0.7b, ) by Carnegie Mellon University: VOICE's English words (JIANT 0.8.5), a subset of ~2100 common words with their pronunciations, packed into the firmware at build time (`tools/gen_lyrics.py`) | BSD-2-Clause | `tools/lyrics/en_dict.txt` (the notice in its header), `LICENSES/BSD-2-Clause-CMUdict.txt` | | X0X by charlesvestal (), a Felucca fork: the design of the browser emulator (the worklet, the device clock driven by its audio, the exports); its files credit it in their headers | GPL-3.0 | `web/emu/` | | DotGothic16 font by The DotGothic16 Project Authors (): the browser emulator's knob labels, served with its page (cut to printable ASCII; the font declares no Reserved Font Name) | SIL OFL 1.1 | `web/emu/fonts/DotGothic16-subset.woff`, `LICENSES/OFL-DotGothic16.txt` (also `web/emu/fonts/OFL.txt`) | | JieLi AC79 SDK by JieLi Technology: three of its files go into every `.fwsc` package (below); none are in this tree | Apache-2.0 | `LICENSES/Apache-2.0.txt` | | Skiff by illuminus5 (), a Felucca fork: the designs of JIANT 0.9.12's 12 voices with the second core and the factory presets' sound types (written anew; no code copied) | GPL-3.0-only | credit only (`firmware/src/voice.c`, `firmware/src/core.h`) | | MIDI LEARN from Felucca 1.5 by Leo Kuroshita (Hügelton Instruments), ported and modified for JIANT 0.9.12 | GPL-3.0-only | `firmware/src/midi_learn.c`, `firmware/src/midi_control.c` | On the device, HOME held > ABOUT opens the information screen; turning PRESETS scrolls on into CREDITS, a short list of these authors, licences and source URLs. ## JieLi SDK files in the packages (Apache-2.0) A `.fwsc` package made by `tools/build.py` (with `tools/fm1pkg_make.py`; this is the package the web installer installs) holds three unmodified files from the JieLi AC79 SDK (, `cpu/wl82/tools/`). They are read from your SDK checkout at build time (see BUILDING.md); no SDK files are in this tree. | File in the package | What it is | | --- | --- | | `uboot.boot` | the first-stage boot loader (SPL) | | `cfg_tool.bin` | the chip configuration block | | `eq_cfg_hw.bin` | the default hardware EQ table | They are licensed under the Apache License, Version 2.0 (`LICENSES/Apache-2.0.txt`), not under the GPL, and their copyright stays with JieLi Technology. The SDK has no NOTICE file. Apache-2.0 files may be distributed together with GPL-3.0 code; Felucca itself stays GPL-3.0-only. Every distribution of a package carries the licence texts with it: the release folder (`tools/build.py --release`) and the site (`web/make_site.py`, next to the package in `firmware/` and linked from the installer page). ## No vendor material No M-VAVE material is part of Felucca. The firmware links no vendor code and contains no vendor data, and the packages hold only Felucca and the three SDK files above. The installer's "Return to official V15" holds only the official file's size and SHA-256: you select the official firmware file you downloaded yourself, and it is checked and installed in your browser, never uploaded or redistributed. ## Contributions Contributions are welcome under GPL-3.0-only. ## Trademarks "Felucca" and "Hügelton Instruments" are names of Hügelton Instruments. "M-VAVE" and "FM-1" are trademarks of their respective owners. Felucca is independent firmware that runs on FM-1 hardware. It is not affiliated with, endorsed by or supported by those owners. ## Radio Felucca never enables the Bluetooth / Wi-Fi radio of the hardware.