— Version history
What’s new
SLOOP 2.0 came out on 4 October 2026; fifteen releases later it is at 2.8.5. Here is what each one added, in our own words, linked to where the guide covers it. The 2.8 releases since 21 October are mostly fixes. This guide is written for 2.8.5 — updating keeps your projects, presets, samples and settings (see updating).
2.8.5
FM-1s with the newer flash chip can save and update
- Newer FM-1s carry a UC25HQ80 flash chip (mostly units bought on AliExpress from late 2026). SLOOP didn’t recognise it, so saving failed with a
flash errorand the update loader wouldn’t install. Both chips now work. In the guide →
- Newer FM-1s carry a UC25HQ80 flash chip (mostly units bought on AliExpress from late 2026). SLOOP didn’t recognise it, so saving failed with a
2.8.4
A clean-up release: quieter note tails, wider unison, strings in tune
- No more buzz on the tails of fading notes, on the 3.5 mm output and over USB. In the guide →
- UNISON voices no longer start in phase, so unison sounds match POLY in level. In the guide →
- PHYS strings play in tune; NZ ARCADE, SAMPLE and GRAIN keep rising over the top keys. In the guide →
- A firm press of up to a second on a layer button still opens its pages. In the guide →
- On REC READY, each knob changes only its own value. In the guide →
- The SONG screen’s confirmations always ask again. In the guide →
- The way back to the official firmware is M-UPGRADE with V16, or Clipper’s installer page if M-UPGRADE can’t see the FM-1. In the guide →
+ 3 bug fixes
2.8.3
Hold a note under others
- On a POLY track, a held note now carries on under the notes you record over it, on playback and in free takes too; on the NOTES page a note’s LEN can stretch under later notes. In the guide →
- Recording on a MONO or LEGATO sound shows
MONO: SET VOICE POLYthe first time you play over a held key. In the guide → - On a busy beat the kick no longer drops out: a drum hit takes its own sound’s voice first, and the kick’s last. In the guide →
- A quick tap on a button no longer flashes its layer: a layer shows after 0.35 s, or as soon as you use a key or knob. In the guide →
- A sample or slice played again starts cleanly with its ATK. In the guide →
- If the second core misreads under heavy load, SLOOP carries on with one core instead of crashing. In the guide →
+ 1 bug fix
2.8.1
The step sheet moves out of the way
- The per-step sheet (hold OCT+) moves to a band at the foot of the screen, leaving the piano roll and drum grid in view, and remembers the row you used last. In the guide →
- With FX held, SELECT sets only the punch-in fade and no longer nudges the tempo. In the guide →
2.8
A piano roll, the step sheet and filter resonance
- The NOTES page: a piano roll for the synth tracks, edited note by note with the four knobs. In the guide →
- A per-step sheet on OCT+ held — SLIDE, NUDGE, FILL, MOVE, COPY, DELETE — on the NOTES page, and on the DRUMS grid with RATCHET in place of SLIDE. In the guide →
- The TRACKS screen shows which section, A–D, is playing. In the guide →
- Resonance for the per-track filter, 0–10, in the HOME menu (
FILTER RESO). In the guide → - The FX filter works on the drum track too. In the guide →
- Drum TUNE shapes the brightness of the tone-less sounds on the synthesised kits. In the guide →
- A settable fade for the punch-in effects, from instant to about a third of a second. In the guide →
- A steadier reading of external MIDI clock. In the guide →
- MIDI Bank Select (CC 0) reaches every preset past the first 128. In the guide →
- USB RESCUE (hold OCT- at power-on) opens reliably. In the guide →
- The in-browser return to stock is gone; use M-VAVE’s M-UPGRADE instead. In the guide →
+ 2 bug fixes
2.7.1
No more crash screen from the second core
- When the second core falls behind, SLOOP now stops it safely — a short glitch, and the music goes on — instead of showing a red crash screen and restarting. In the guide →
- The black keys pick the drum sound on the DRUMS grid and in the SEQ layer; drum sounds picked with a knob are silent unless
DRUM PREVIEWis on. In the guide → STEP ADVANCEin the HOME menu’s SEQ section, and CC 11 expression. In the guide →
2.7
Two cores, fifteen arp modes and the LIVE page
- The audio now runs on both processor cores of the FM-1, roughly doubling the headroom for voices and effects. On by default. In the guide →
- Nine new arp modes, fifteen in all, and ORD follows the order you pressed. In the guide →
- KBD HOLD: HOLD with the arp off holds your chord. In the guide →
- Samples that loop while held, with zero-crossing loop points. In the guide →
- Tune and decay for every drum sound on the DRUMS screen’s new SOUND page. In the guide →
- Favourite sounds at the top of the PRESETS list. In the guide →
- QUANT off on the REC screen keeps your timing as nudges. In the guide →
- GLO → MIDI 3: punch-in effects over MIDI, a 1–16 drum map, the buttons over MIDI and clock out on USB. In the guide →
- Knob acceleration, and LEVEL and PAN that glide. In the guide →
- The web editor’s LIVE page, songs as files and a playlist. In the guide →
- Your own screen colours from the editor’s Theme page. In the guide →
- SAVE → SECTION A–D replaces PROJECT 1–4: the FM-1 holds one song. In the guide →
2.6
27 punch-in effects, insert effects and MIDI learn
- Eleven more punch-in effects on the black keys. In the guide →
- An INSERT effect on every track, LFO 2 with tempo sync, ENV SYNC and the ANALOG filter as LP, BP or HP (from Felucca 1.4 and 1.5). In the guide →
- MIDI LEARN: GLO + F#3, then a SLOOP knob and a controller knob. In the guide →
- TEXTURE: a vinyl, tape, rain, wind, radio or room bed under the mix. In the guide →
- Live drum mutes from the EDIT layer. In the guide →
- A MIDI channel for each track, sustain pedal, pitch bend and Program Change. In the guide →
- Reverb and echo throws on FX + OCT- and FX + OCT+. In the guide →
- The web editor offline: as one downloaded file, or as an installed app. In the guide →
- A bolder screen font, and a look-ahead master limiter. In the guide →
+ 6 bug fixes
2.5
Physical models, noise and 153 sounds
- PHYS, an eleventh engine of physical models: guitars, sitar, bells, hand drums. In the guide →
- NOISE, a twelfth engine, from analogue noise to digital. In the guide →
- 153 factory sounds, up from 76, all level-matched. In the guide →
- The editor gets a piano roll, MIDI file import and export, and a Song page. In the guide →
- USB audio at 48 kHz too, for phones. In the guide →
- Drum synth: four synthesised kits of your own, SYN1–SYN4. In the guide →
- Whole DX7 cartridges stored in one go. In the guide →
- A delay send for the drums, and MIDI CCs for the sound. In the guide →
- Swing reads 0–100 instead of 50–75 %. In the guide →
+ 4 bug fixes
2.4
FM6, parameter locks, micro timing and fills
- FM6: six-operator FM with DX7 patches, imported in the web editor. In the guide →
- Parameter locks, 24 a track. In the guide →
- Micro timing: nudge a step up to half a step either way. In the guide →
- Fill conditions, and fills called from the GLO layer. In the guide →
- Quick chains of sections. In the guide →
- The sequencer to MIDI out, and clock-only MIDI in. In the guide →
- CHORD+, STRUM and VLEAD. In the guide →
- Your own drum kits in USR1–USR4 and USR3+4. In the guide →
- The visualiser, a filter on each track and longer divisions up to two bars. In the guide →
+ 10 bug fixes
2.3
USB audio, MIDI in on the jack and clock
- The FM-1 becomes a USB audio input. In the guide →
- A MIDI keyboard on the 3.5 mm jack. In the guide →
- MIDI clock in over USB or the jack. In the guide →
- The REC screen: mode, length and start. In the guide →
- Lights for playing in the dark. In the guide →
- Backup and restore in the web editor. In the guide →
+ 7 bug fixes
2.2
A new drum engine and a real grand piano
- Every synthesised drum rebuilt, with new PHONK, AMAPIANO, GARAGE and D.HOUSE kits and a sampled ACOUSTIC kit. In the guide →
- Sounds browsed by kind; GRAND PNO recorded from a Steinway. In the guide →
- Lock a layer open: hold its button and tap HOME. In the guide →
- A stereo chorus and a new reverb. In the guide →
+ 8 bug fixes
2.1
Songs, live
- Hold SAVE: play sections A–D on the next bar, save into them and record the song as you play. In the guide →
- Keys 1, 5, 9 and 13 glow dimly as landmarks while a layer is held. In the guide →
2.0
Hold a button, touch a key
- Every function button becomes a layer while held. In the guide →
- 16 drum sounds on the white keys, ghost and hard hits and ratchets. In the guide →
- Note repeat, erase as it plays, step entry, one-key chords, mute, solo and tap tempo. In the guide →
- Undo and redo, hold REC to clear, and autosave. In the guide →
- The master DUST, DUCK and DJ filter. In the guide →
Full details, including every bug fix, are in SLOOP.md’s version history and the GitHub release notes .