— Interactive guide · SLOOP 2.8.5
SLOOP
The FM-1 as a four-track groovebox
SLOOP is free, open-source firmware that turns the M-VAVE FM-1 into three synths and a drum machine you play live. This guide explains it properly: what you give up and how to flash it safely, a clickable panel that shows what every key and knob does in each of the seven layers, all twelve engines, the sequencer, song mode and MIDI — searchable in a keystroke, with the community’s best videos beside the topics they cover.
- chapters
- 12 chapters
- topics
- 109 topics
- key combos
- 142 key combos
- videos
- 4 videos
Before you flash
SLOOP replaces the FM-1’s firmware, and its developer still calls it a beta: install at your own risk. There is no Bluetooth MIDI. Owners have reported a new unit that stopped responding mid-install, failed returns to stock and failed installs on V16; FM-1s with the newer UC25HQ80 flash chip need 2.8.5 or later. Read the risks, each with its source, and make a backup before you start.
— Where to start
Flash it safely
What you give up, what has gone wrong for others, and how to install, rescue and go back.
- 1What you give up while SLOOP is installed
- 2What you need
- 3Known risks and owner reports
- 4Installing SLOOP
- 5USB rescue and power-on combinations
- 6Going back to the official firmware
Your first hour
Tracks and layers, a beat in a minute, recording, undo, and saving your loop as a section.
- 1Four tracks, four colours
- 2Tap for pages, hold for a layer
- 3Your first beat in a minute
- 4The 16 drum sounds
- 5What REC does
- 6Free take: the loop follows you
- 7Undo, clear and start again
- 8Saving and playing sections
Deeper grooves
Ghost notes and ratchets, step entry, the piano roll, parameter locks, micro timing and fills.
- 1Ghost notes, hard hits and ratchets
- 2The SEQ layer: steps under your fingers
- 3The NOTES page: a piano roll for synth tracks
- 4Parameter locks
- 5Nudge: micro timing
- 6Fill conditions
- 7Chord mode: a chord under every finger
Play it live
Locked layers, punch-in effects, erase and note repeat, mutes and fills, chains and the LIVE page.
- 1The seven layers at a glance
- 2Locking a layer open
- 3Punch-in effects
- 4Erase as it plays
- 5Note repeat
- 6Mutes, solos, fills and tap tempo
- 7Quick chains
- 8The LIVE page
— Explore the panel
Hold a button, touch a key
Pick a control, or hold a layer.
Under SLOOP every function button has two jobs: tap it for its pages, hold it and the 16 white keys and four knobs change job. Choose a layer above to see what each key and knob does, and a track to see the keys as a synth or as the drum kit.
Our own schematic of the FM-1 running SLOOP 2.8.5, from GUIDE.md §2, §5, §9 and §15 · not to scale
— Contents
12 chapters, start anywhere
Before you flash
What SLOOP replaces, the risks, installing it, rescuing it and going back to stock.
What SLOOP is · Reading this guide · What you give up while SLOOP is installed · What you need · Known risks and owner reports · Installing SLOOP · Updating and changing versions · USB rescue and power-on combinations · Going back to the official firmware · Specifications
Panel & big ideas
Four coloured tracks, tap versus hold, the seven layers and every screen.
The front panel under SLOOP · Four tracks, four colours · Tap for pages, hold for a layer · Locking a layer open · Every button on its own · Pages, the SELECT knob and GO values · The screens · The visualiser · The HOME menu · Lights and knob feel
First beat & playing the keys
A beat in a minute, then scales, one-finger chords, CHORD+ and the arpeggiator.
Your first beat in a minute · Playing the synth tracks · Levels and force: dynamics without velocity · Key and scale · Chord mode: a chord under every finger · CHORD+: the black keys change the chord · Strum and voice leading · The arpeggiator · The 15 arpeggiator modes · KBD HOLD: sustain without an arpeggio
The drum track
16 sounds on the white keys, 37 kits, ghost notes, ratchets, the grid and kits of your own.
The 16 drum sounds · Ghost notes, hard hits and ratchets · The 37 drum kits, and yours · The DRUMS screen · Tuning and shaping each drum · Your own sampled drum kits · Your own synthesised kits (SYN1–SYN4)
Engines & sounds
The twelve engines behind 153 sounds, six-operator FM with DX7 patches, envelopes and LFOs.
The sound bank · User presets · The twelve engines · ANALOG and TRIO · DIGITAL and PHASE · LOFI and NOISE · SAMPLE and GRAIN · VOICE and WHEEL · PHYS: physical models · FM6: six-operator FM · DX7 patches and the FM6 editor · Polyphony and voice modes · The envelope · The LFO
Recording
Play it in: free takes that set the tempo, count-ins, overdubs and keeping your own timing.
How recording works · What REC does · The REC screen · Free take: the loop follows you · Keeping your own timing (QUANT off) · Chords, held notes and legato · Metronome, tempo and swing · Recording from a MIDI keyboard
Step sequencer
64 steps a track, the NOTES piano roll, parameter locks, micro timing and fills.
How the sequencer works · The SEQ layer: steps under your fingers · The NOTES page: a piano roll for synth tracks · The step sheet: slide, nudge, fill, move, copy, delete · The PATTERN page: length, division, swing and gate · Nudge: micro timing · Parameter locks · Fill conditions
Performance layers
27 punch-in effects, erase as it plays, note repeat, live mutes, solos and fills.
The seven layers at a glance · Punch-in effects · Reverb and echo throws · Erase as it plays · Drum mutes · Note repeat · Mutes, solos, fills and tap tempo
Effects & mix
The master bus, a filter and an insert on every track, sends, slicer and texture beds.
The signal path · Master effects: DUST, DUCK, FILT, ROLL · The track filter · Sends: chorus, delay and reverb · The slicer · Insert effects · Texture beds · Mixing and tempo
Song mode, undo & saving
Four sections played live, chains, a song recorded as you play, undo and autosave.
Sections and the one song · Saving and playing sections · Quick chains · Recording a song as you play · The SONG screen · Undo, clear and start again · The SAVE pages · Autosave · Keeping more than one song
MIDI, clock & USB audio
Keyboards on the jack, a channel per track, clock in and out, CCs, MIDI learn and recording over USB.
Where MIDI comes in · MIDI channels and the MIDI 2 page · MIDI out · Following an external clock · Sending clock: CLOCK OUT · MIDI CCs, sustain and pitch bend · Program Change and Bank Select · MIDI LEARN · MIDI 3: effects, drum map and remote buttons · Recording over USB audio
Web editor, samples & backup
The browser editor and its LIVE page, your own samples, screen themes, backups and fixes.
The web editor · The editor’s pages · Piano roll and MIDI files · The LIVE page · Your own samples · Your own screen theme · Backup and restore · Troubleshooting
— Muscle memory
The combos you’ll use every day
In SLOOP you hold a button and then press a key or turn a knob. A few of those combinations are worth learning by heart. The full cheat sheet has all 142, filterable by key and printable.
Open the cheat sheet- OCT- + KEY
- Plays and records the hit as a GHOST note.On the drum track
- FX + WHITE KEY
- Plays that key’s punch-in effect on the whole mix while held.
- SEQ + STEP
- Sets an empty step at once, or clears a set step with its nudge, locks and fill condition.
- EDIT + OCT-
- Undoes the last change.
- GLO + KEY 1–4
- Mutes or unmutes track 1–4.
- SAVE + KEY 5–8
- Stores the working loop as section A–D; over a used section, press the same key again within 3 s.
- SAVE + KEY 1–4
- Starts section A–D on the next bar, every track from its first step.While playing
- Hold OCT- while switching on
- Starts USB rescue (
SLOOP USB RESCUE), so you can install again from the browser.
— Watch
Learn it from the community
Sloop - Firmware for the M-VAVE FM-1 Complete tour
3dSam
A seven-minute tour of SLOOP 2.2 from 3dSam, the channel behind SLOOP, played on SLOOP itself. Much has been added since, but the layers it shows work the same way.
a fairly deep dive into sloop v2.3 (m-vave fm1 custom firmware)
BIG UMAMI
Twenty-four minutes cut from a two-hour live stream on version 2.3, starting from a blank project. Older than 2.8 — 76 sounds then — but the workflow carries over.
SLOOP 2.8 Completely Changes How You Sequence on the FM-1
PhilipsKnobs
A first look on 2.8’s release day: building a loop from scratch with the new piano-roll sequencer — note lengths, chords and drum patterns.
An independent guide by boog.ie, written for SLOOP 2.8.5 (4 November 2026). It is not affiliated with SLOOP’s developer or with M-VAVE; M-VAVE and FM-1 are trademarks of their owners, and DX7 of Yamaha Corporation. It is written in our own words from SLOOP’s complete guide, its manual, README and release notes (GPL-3.0), with background from Felucca by Leo Kuroshita / Hügelton Instruments, on which SLOOP is built. Owner reports are labelled as such and linked; when in doubt, SLOOP’s own documents win. SLOOP on GitHub