Emerald YM
A real YM2612 emulator, a lightweight Sega-style PSG and an endless sequencer turn the FM-1 into a small chiptune instrument.
- Custom firmware
- Beta
- Medium brick risk
- Reversible
Source codeWebsite: github.com
This project hasn't been claimed by its maintainer yet, so its details come from the community. Is it yours? Claim it
Emerald YM 0.10.0 (beta) — Caspius Labs
Exact hardware-tested firmware for M-VAVE FM-1. The .fwsc attached here is the exact file installed and tested in PR #11, published without rebuilding.
MIDI IN/OUT with EDIT
- EDIT dim: receive notes/effect CCs over USB and the minijack.
- EDIT bright: send physical keyboard and sequencer notes through USB MIDI OUT; the header shows USB MIDI OUT. Local synthesis continues. Incoming note/effect messages are ignored in OUT to prevent echo.
- USB Clock (24 PPQ), Start/Continue/Stop, diagnostics and stereo 16-bit/44.1 kHz USB capture remain available in both modes. K1 returns to internal tempo. EDIT resets to IN at boot and is not saved.
- Output channels: keyboard 1, FM bass/lead 2–3, FM chords 4–6, PSG arp/noise 7–8, drums 10 (36/38/42/46).
- The minijack remains MIDI IN. Physical MIDI OUT needs a PC/USB host routing Emerald USB MIDI to an external interface such as UM-ONE. No Bluetooth output or outgoing Clock/transport is included.
- GLO / USB ONLY retains physical-audio mute with USB capture active.
Physical validation
A 60-second 180 BPM run captured MIDI OUT, USB audio and status simultaneously: average sampled CPU 45.98%, maximum 72%, longest block 4,212 us, XRUN 0 / overload 0 / failed boots 0. The main session captured 2,047 Note Ons across all nine assigned channels; Stop released all captured notes. Separate tests established keyboard chords, held-key cleanup when EDIT returned to IN and USB input before/after switching. The owner confirmed correct EDIT LED/header and smooth backing. The complete stereo USB recording was 81.41 s, with no clipping in the analyzed body.
This is short-run USB validation, not a long-session or destination-synth test. TRS input was checked on earlier 0.9.0, not retested on exact 0.10.0. Old V15/Dinghy installation/recovery evidence remains specific to exact 0.4.3.
Exact package and matching source
- Asset:
emerald-ym-0.10.0.fwsc— 609,677 bytes. - SHA-256:
195cd2d1a504d5936e79cde227d64d2d8d1bd407945e8156dac795f682d59401(also inSHA256SUMS). - Running identity:
FM-1_68001000. - Tag
v0.10.0/ matching firmware source:e906fbc5eb3c91e45c95101c46bd0d674eef533d. Use the automatic source archive for this tag; documentation-only 0.10.1 does not replace the firmware. ui-preview.pngis a capture from the exact native firmware renderer, not a device photograph.
Full updated instructions, archived hardware reports and the current README are in PR #11. That PR remains open for review; this release does not merge it. Matching firmware source.
Combined firmware license: GPL-3.0-only; see the source's LICENSING.md for component terms. Emerald YM is independent of Sega, Yamaha and M-VAVE.
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 Emerald YM v0.10.0 work on your M-VAVE FM-1?
No reports yet for v0.10.0.
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 ("Quick controls"):
Start with MASTER low, then press PLAY. The sequencer is paused after boot.
Control Function in 0.10.0 PLAY Start/pause the backing sequencer; live keys still work in pause REC Generate a new seed and sequence SAVE Pause the backing and save instrument levels/effects and K1–K4 after notes have settled SEQ Toggle mutation between 0 and 35 K1 / K2 / K3 / K4 Tempo / melody density / mutation / transpose SELECT Select one of twelve instruments PRESETS Set the selected instrument's level, 0–100% FX Select DECAY, COLOR or ECHO for editing GLO Toggle USB ONLY; lit when speaker/headphones are digitally muted ALGORITHM Set the selected effect amount, 0–100% ARP Enable/disable all PSG, including live keys EDIT Dim: USB/TRS note input; bright: physical keyboard + sequencer note output over USB Keyboard Up to three live PSG notes, F3–G5 MASTER Overall output level; the on-screen red slider follows the physical knob …
Risk and recovery
- Brick risk
- Medium
- Reversible
- Yes
- Requires opening the device
- No
From the project's README ("Verified installation paths"):
Physical tests on 2026-10-27 used the exact 0.4.3 package linked above, official M-VAVE V15 and Dinghy 0.3:
Transition Result Emerald 0.4.3 → official V15 Passed Official V15 → Emerald 0.4.3 Passed Emerald 0.4.3 → Dinghy 0.3 Passed Dinghy 0.3 → Emerald 0.4.3 Passed All four used normal USB MIDI updating and returned the expected running identity, without a rescue shortcut or manual power cycle. The owner confirmed screens and audible keys in V15 and Dinghy. After each return, Emerald passed 20 seconds of continuous playback: CPU MAX 67%, XRUNS 0, overload 0. Emerald 0.4.3 was restored at the end. Package hashes, raw reports and scope.
A subsequent USB data-interruption test on battery passed: disconnect at 25% of the loader transfer, reconnect, restart installation and return to 0.4.3. The following 20-second continuous playback test passed (CPU MAX 67%, XRUNS 0). This used the same image already installed; equal sectors may be skipped, so it does not prove interrupted changed-sector writing or power-loss recovery.
These results apply to the exact linked package, not earlier review builds with the same 0.4.3 identity, release 0.4.0, arbitrary firmware versions or every device. They do not establish interrupted-write recovery or compatibility/preservation of other firmware's data. …
Releases
| Version | Name | Released |
|---|---|---|
| v0.10.0 | Emerald YM 0.10.0 (beta)Pre-release | 28 October 2026 |
| v0.7.0 | Emerald YM 0.7.0 — betaPre-release | 27 October 2026 |
| v0.6.0 | Emerald YM 0.6.0 — betaPre-release | 27 October 2026 |
| v0.4.3 | Emerald YM 0.4.3 — betaPre-release | 27 October 2026 |
| v0.4.0 | Emerald YM 0.4.0 — betaPre-release | 27 October 2026 |
| v0.3.1 | Emerald YM 0.3.1 — betaPre-release | 27 October 2026 |
Credits, license and support
- License
- GPL-3.0