GHOULBOX
GHOULBOX is dungeon-synth firmware for the M-VAVE FM-1: a fork of Felucca by Hügelton Instruments (1.4.1), tuned for dark ambient, medieval and fantasy synth music, from Old Tower and Hole Dweller to Mortiis-era dungeon synth.
- Custom firmware
- Beta
- Medium brick risk
- Reversible
Source codeWebsite: ghoulbox.messy.quest
This project hasn't been claimed by its maintainer yet, so its details come from the community. Is it yours? Claim it
Support the developers
Links from the project's GitHub. The money goes to them, not to Firmware Hero.
GHOULBOX 2.4: change the scene live, sleep timer, FREEZE, the sequencer to your DAW, and three fixes.
Install or update: first save a backup (the installer doesn't make one): open the web editor, connect the FM-1, and on the Settings tab press Save backup. Then open https://ghoulbox.messy.quest/webapp/installer/ in Chrome or Edge and press Install.
User guide (PDF) (updated for 2.4; printer-friendly) · Play it in your browser · Hear every sound · Video lessons · Every free FM-1 firmware
What's new in 2.4
- SCENES: change the music live. Tap HOME on the home screen until SCENES shows (after DREAM). Its first five white keys switch to DUNGEON (F3), CRYPT (G3), TAVERN (A3), CHAPEL (B3) or BLANK (C4) while the music plays: a short fade out, the scene's four sounds, patterns and tempo, a fade back in. Made for game masters: the party walks into the tavern, you press one key. A scene replaces your four tracks, so save first if you want to keep them.
- SLEEP. MENU › SYSTEM › SLEEP: OFF, 30, 60 or 90 minutes. After that long without touching the FM-1 (or playing it over MIDI), the music fades out over two minutes and stops. Touch anything to bring the sound back. For game nights, study and sleep.
- FREEZE: keep the pass you liked. DREAM's notes each have a chance, so every pass is a little different. When one sounds right, hold SEQ and press F4: the selected track's steps become exactly what that pass played, and EVOL turns off so the piece stays put. Hold SAVE to undo.
- SEQ OUT. MENU › MIDI › SEQ OUT ON sends what the sequencer plays (DREAM's parts too) out over USB MIDI, each track on its own channel, so the FM-1 can play your DAW's instruments. OFF by default. In the DAW, don't send that MIDI back to the FM-1, or every note plays twice.
Fixed
- The CRYPT kit's shaker no longer cuts off its jingles (they were treated as a hi-hat pair).
- Letting go of the FX layer now puts a MIDI CC74 filter back where your controller left it, instead of opening it.
- The web editor names a CRYPT kit's lanes: FRAME, ROPE, SLAP, SHAKR, JINGL, TIMP, STICK, GONG.
Removed
- MENU › SYSTEM › USB SERIAL and the developer console behind it (off by default since 1.2). That made room for the above, and a Mac now always finds the FM-1's USB audio.
Your saved music
Projects, user presets and settings load and sound as before.
Notes
- 2.4 has not been tested on an FM-1 yet. Its full test suite and the browser emulator (the same firmware) pass. Save a backup first, and install at your own risk; you can always go back to 2.3.2 or the official firmware with the installer.
- The FM-1 Firmware Hub picks up
ghoulbox-2.4.fwscfrom this release.
Before you start
- How hard is it?
- EasyCopy a file or use a web page. No extra software.
- What you need
- A USB or MIDI cable
- Comfort with the command line
- A computer
- Can it break my device?
- Small chance of trouble, with a way to recover.
- Can I undo it?
- Yes. You can go back to the official software.
Did it work for you?
Did GHOULBOX ghoulbox-v2.4 work on your M-VAVE FM-1?
No reports yet for ghoulbox-v2.4.
One-tap reports from owners. Bricked reports are checked before they count.
Compatibility
Devices: M-VAVE FM-1.
No compatibility information yet.
Getting started
From the project's README ("Install"):
In Chrome or Edge on a computer, with the FM-1 on a USB data cable and no other music app open:
ghoulbox.messy.quest/webapp/installer
First save a backup: the installer doesn't make one. Open the web editor, connect, and on its Settings tab press Save backup (your music, sounds, samples and settings, to your computer).
Then press Install. If it stops after "update mode", replug the USB cable and press Install again: the FM-1 stays in update mode until the install is finished.
To go back, install Felucca from its installer and restore the backup in its editor; its "Return to official V15" returns to M-VAVE's firmware. The package (and the user guide) are also on the Releases page.
Something wrong, or a sound you want? Open an issue; plans are in the roadmap.
To build it yourself (JieLi toolchain and AC79 SDK, see BUILDING.md):
./build.sh python3 tools/ghoulboxserve.py # http://localhost:8000/webapp/installer/
Risk and recovery
- Brick risk
- Medium
- Reversible
- Yes
- Requires opening the device
- No
From the project's README ("If the FM-1 does not start"):
- If GHOULBOX itself won't start, switch the FM-1 off, then on again while holding OCT-: it starts in GHOULBOX's USB rescue (no sound, no menu), and the web installer can install again from there. Two failed starts in a row open the rescue on their own.
- If an update is interrupted and the FM-1 stays black, check whether a computer sees it as a USB device named WL80UBOOT (or a USB mass-storage device with ID 4C4A:8057). That is the chip's built-in boot mode: try another USB data cable, close every other app that uses MIDI, and run the web installer again.
- If it stays in boot mode, FM-1 Transporter reads and writes the FM-1's flash from a Mac through a Seeed XIAO RP2040 (three wires to the FM-1's USB lines). Back up the flash first, then write the official firmware (M-VAVE's FM-1.fwsc).
- Still stuck? Open an issue.
Releases
| Version | Name | Released |
|---|---|---|
| ghoulbox-v2.4 | GHOULBOX 2.4Latest | 24 October 2026 |
| ghoulbox-v2.3.2 | GHOULBOX 2.3.2 | 17 October 2026 |
| ghoulbox-v2.3.1 | GHOULBOX 2.3.1 | 17 October 2026 |
| ghoulbox-v2.3 | GHOULBOX 2.3 | 17 October 2026 |
| ghoulbox-v2.2 | GHOULBOX 2.2 | 17 October 2026 |
| ghoulbox-v2.1 | GHOULBOX 2.1 | 12 October 2026 |
| ghoulbox-v2.0 | GHOULBOX 2.0 | 12 October 2026 |
| ghoulbox-v1.4 | GHOULBOX 1.4 | 10 October 2026 |
| ghoulbox-v1.3 | GHOULBOX 1.3 | 10 October 2026 |
| ghoulbox-v1.2 | GHOULBOX 1.2 | 10 October 2026 |
| ghoulbox-v1.1 | GHOULBOX 1.1 | 7 October 2026 |
| ghoulbox-v1.0 | GHOULBOX 1.0 | 7 October 2026 |
Credits, license and support
- License
- GPL-3.0