FM-1 firmware · v2.7.1

SLOOP

With SLOOP the FM-1 becomes a live groovebox: one drum machine plus three synth tracks. Hold a function button and the keys and knobs take on a new job (record, erase, repeat notes, set steps, change key, mix, arrange); tap the same button and its sound-design pages open. It is for people who want to build beats and song sections on the FM-1 itself, with no computer.

Turns it into: A four-track live groovebox: three synth tracks and a drum machine, layers, punch-in effects, song sections, samples with held loops and tails
Best for: Making beats and song sections on the FM-1 itself, live
Install: hub or GitHub release

Where everything is on SLOOP

TapSwipe across the panel, then tap any control to see what it does on SLOOP.

Printable skin (PDF)Key strips (PDF)

Start here

The modes

Mode	How to get there
TRACKS screen (the performance view)	Tap HOME
Visualiser	Tap HOME while on TRACKS (HOME again closes it)
A button's pages	Tap FX, SEL, ENV, LFO, EDIT, GLO, ARP or SEQ. Tap again for the next page
SEQ STEP page (synth tracks)	Tap SEQ on a synth track
SAVE pages	Tap SAVE on any page except TRACKS, DRUMS and SONG
DRUMS screen (grid, kit or sound)	Drum track selected, tap EDIT or SEQ on TRACKS. It returns to its last page; turn SELECT fully left for GRID
SONG screen	Tap SAVE on TRACKS or DRUMS, or hold SAVE and press white key 16
A layer	Hold FX, EDIT, ARP, SEQ, SEL, GLO or SAVE (the screen changes after a moment)
A layer locked open	Hold the layer button and tap HOME. Any button except PLAY, REC, OCT- and OCT+ unlocks it
Rec ready, count-in, free take	Press REC while stopped
Menu	Hold HOME for 0.7 s
Keyboard hold	Synth track: ARP MODE OFF, ARP 2 HOLD ON

White keys are counted 1 to 16 from the lowest (F3) to the highest (G5). A tap means pressed and released in under about half a second with nothing else touched.

Play and pick sounds

Do this	What happens
Turn ALGORITHM	Picks track 1, 2 or 3 (synths) or 4 (drums). Works on every screen except the SONG screen, the menu and a free take
Turn PRESETS on TRACKS or the PRESETS page	Changes the selected track’s sound: favourites, factory sounds by kind, then user sounds. A running arp keeps its settings and notes. Held keyboard notes stop. If the new sound brings an arp, HOLD becomes its latch; otherwise keyboard hold remains available. On the drum track: the kit
Keys, synth track	Play notes. OCT- / OCT+ move an octave (range -3 to +3); both together return to 0
Keyboard hold on	Notes or chords continue after release. A fresh press with no keys down replaces them; presses while keys are down add notes. While a chord key is down, black keys can change its held chord tones. HOLD OFF, enabling the arp or changing the sound ends the held notes
Release a user SAMPLE note with the engine LOOP switch on, ARP, HOLD and sustain off	LOOP finishes its current pass; LOOP+TAIL leaves its loop and plays the tail. ENV REL can fade either sooner. Factory loops keep their earlier behavior
Keys, drum track	The 16 white keys play the 16 drum sounds. A black key doubles the white key to its left
Hold OCT- or OCT+ while hitting drum keys	Ghost or hard hits
Turn MASTER	Output volume. USB audio follows it unless USB AUDIO is FULL. If the editor’s LIVE page set the level, move MASTER far enough to take control back
KNOB 1 to 4 on TRACKS	Global swing, track level (unmutes a muted track), track length in steps, track pan

Record

Do this	What happens
REC while playing	Recording starts right away on the selected track. A second REC ends the take and the loop carries on
REC while stopped	Arms (REC light blinks). Your first note, or PLAY, starts the loop and the recording. REC again disarms
REC in an empty project, then play	A free take with no click. Press REC on the downbeat after your last bar: it becomes a 1, 2 or 4 bar loop and sets the tempo. QUANT OFF keeps timing offsets as nudges. PLAY throws the take away; it ends by itself after 24 s
KNOB 1 / 2 / 3 while armed	MODE: free or tempo (empty project only). LENGTH: a loop of one, two or four bars. START: begin on your first note, or let PLAY give one bar of clicks first
KNOB 4 while armed	QUANT: right ON, left OFF. OFF keeps the first note or hit’s timing as a step nudge; later notes on that step share it. Arps and rolls stay on the grid. This setting is kept
PLAY during the count-in	Back to armed. REC cancels and disarms
Turn ALGORITHM while recording	The recording moves to the next track
Overdub a note across a held pattern note in POLY mode	The held notes can continue beneath the new note, within the four-note step limit. Step entry still replaces the step
Hold REC about 2 s	Wipes the selected track: its notes, parameter locks, nudges and fill conditions (a ring shows after 0.7 s; release before it closes and nothing changes). Undo returns notes, length and nudges; locks and fill conditions stay lost
REC while the song plays in song mode	Refused until you stop; arming switches back to loop mode

Switching from your firmware

Pick the firmware on your FM-1 now to see what installing SLOOP does to its data.

1 · Back up first, on Stock V15

Stock V15 has no way to back up your voices or patterns. The FM-1 only sends notes over MIDI, never voice data.
One indirect way to back up, from Baud Girl's own docs (not tested by us): installing her FM-1+VA keeps your saved stock presets and patterns, and its browser Device Manager can then save all 128 presets and 16 patterns as files. FM-1+VA is closed source; install it at your own risk.

2 · What happens to your Stock V15 data

Possibly at risk

(the layout is reported or inferred, not read in code)

stock settings (and possibly patterns)
stock Bluetooth data
stock voices (128 user patches, banks A-D)

(weakest evidence: reported)

Everything about leaving Stock V15

Everything else on SLOOP

Shape a sound

Do this	What happens
Tap ENV	ENV, then ENV DEST
Tap LFO	LFO, LFO 2, LFO DEST
Tap FX	FX sends, FILTER, SLICER, INSERT, INSERT 2, DLY, REV/CHO
Tap EDIT	EDIT 1, EDIT 2, FILTER (ANALOG engine only), VOICE, VOICE 2
Tap ARP	The arpeggiator: ARP, ARP 2
ARP page, MODE	OFF, UP, DN, UPDN, RND, ORD, REPEAT, DNUP, UP+8, CONV, DIVG, PINKY, THUMB, WALK, CHORD. ORD follows playing order even when ARP 2 ORD is NOTE; CHORD plays the held chord each tick
Tap GLO	GLOBAL, MASTER, SYSTEM, DRUMS, MIDI, MIDI 2, MIDI 3, TEXTURE, TEXTURE 2
ARP 2, SWG	Swing also applies when the transport is stopped; rates without swing stay straight
KNOB 1 to 4 on a page	The four values shown. Pages with nothing for the drum track show DRUM TRACK there, and the knobs are inactive
Turn SELECT on a page	Previous or next page of the same button, stopping at the ends
PRESETS on a page other than PRESETS	Ignored, so a stray turn cannot swap the sound you are editing

Edit steps

Do this	What happens
Hold SEQ, press a white key	Controls that step on the displayed page: pressing an empty step adds the selected drum hit or recent synth notes; an occupied step is removed on key-up unless a knob adjustment kept it
Hold SEQ, press F#3, G#3, A#3 or C#4	Shows steps 1-16, 17-32, 33-48 or 49-64. OCT- / OCT+ step through the pages too
Hold SEQ, turn KNOB 1 / 2 / 3 / 4	The sound or note new steps get, the step division (1/4, 1/8, 1/16, 1/32, 8T, 16T, 1/2, 1 bar, 2 bars), the track's own swing, its length (1-64)
Hold SEQ and a step, turn KNOB 1 / 2 / 3 / 4	Drums: which sound to edit, its level, ratchet, nudge. Synths: the notes, velocity (1-127), ratchet, nudge (up to 32/64 of a step early or 31/64 late)
Hold SEQ and a step, turn PRESETS / ALGORITHM	A parameter lock on that step: its value, and which parameter (the last sound value you touched comes first)
Hold SEQ and a step, press OCT+ / OCT-	Cycles the fill condition (normal, fill only, no fill) / clears nudge, locks and fill condition
STEP page, play keys	Writes the note or chord into the cursor step; black keys write nothing under WHITE keys or chord mode. Let go of all keys to advance after writing
STEP page, KNOB 1 / 2 / 3 / 4	Cursor, transpose the step, NOTE / TIE / REST (on a note: how many steps it lasts), flag (accent, slide, both)
STEP page, tap EDIT	Clears the cursor step and moves on
DRUMS grid, white keys	Each white key is a step for the drum sound chosen with KNOB 1; a press adds or removes that hit. F#3 to C#4 pick the page of steps
DRUMS grid, KNOB 1 / 2 / 3 / 4	Sound, step, add (right) or remove (left) a hit, hit level
DRUMS kit page, KNOB 1 / 2 / 3 / 4	Kit, drum level, drum reverb, drum pan. EDIT or SEQ cycles GRID, KIT, SOUND; SELECT moves between them and stops at the ends
DRUMS sound page, keys or KNOB 1	Plays and selects the drum sound to edit
DRUMS sound page, KNOB 2 / 3 / 4	Tune (-8 to +7 semitones), decay (-4 to +3 on synthesised kits and SYN1-4; sampled kits only shorten at negative values; 0 unchanged), drum volume shown as 0-100. Changed tune and decay audition the sound when stopped; the settings belong to the loop and each section

Erase, undo and reshape

Do this	What happens
Hold EDIT, press a key while playing	That note (or chord, in chord mode) or drum sound is erased from each step the playhead passes while you hold
Hold EDIT, press a key while stopped	Erased from the whole pattern at once
Black keys on a synth track with chord mode on or KEYS = WHITE	Silent: in the EDIT and ARP layers they erase and repeat nothing
Hold EDIT, press a black key (drum track)	Switches to live mutes: each white key then silences or restores its drum sound while the hits stay in the pattern. A black key toggles back to erasing. Letting go of EDIT keeps the erase/mute choice for the next hold. Mutes are never saved
Hold EDIT, turn KNOB 1 / 2 / 3	Rotate the pattern a step, double it or halve its length, transpose notes. Rotate and double move or copy only the note and drum steps; nudges, locks and fill conditions stay at their existing positions
Hold EDIT, press OCT- / OCT+	Undo / redo, one level, for one track’s notes, pattern length and nudges. Parameter locks and fill conditions do not come back

Key, scale and chords

Do this	What happens
Hold SEL, press any key	Sets the song key for all three synth tracks
Hold SEL, turn KNOB 1 / 2 / 3 / 4	For the selected synth track, the chord type (off, triad, 7th, 9th, sus4, power), scale of all three synth tracks, KEYS (off, snap, white), transpose (plus or minus 24)
Chord mode on, white keys	Each plays a chord of the scale, with C4 as the first degree; keys below C4 carry on downward. On the chromatic scale the chords come from natural minor
Chord mode on, hold a black key	F# flips major and minor, G# adds the 7th, A# makes it sus4, C# adds the 9th, D# inverts. Hold several to combine
Tap SEL	SEL and SEL 2 pages (root, scale, keys, chord; transpose, strum, voice leading)

Performance effects and note repeat

Do this	What happens
Hold FX, hold a white key	A punch-in effect on the whole mix while held. From F3 up: loops of 1/4, 1/8, 1/16 and 1/32, stutter, reverse, tape stop, half speed, low-pass sweep, high-pass sweep, phone, bit crush, alias, 1/16 gate, dotted-1/8 echo, tape wobble
Hold FX, hold a black key	From F#3 up: kill lows, kill mids, kill highs, rewind, octave up, flanger, auto-pan, freeze, 1/8-triplet loop, mono, fade out
Hold FX, turn KNOB 1 / 2 / 3 / 4	Master filter (left low-pass, right high-pass), DUST, DUCK, the selected track's filter
Hold FX, hold OCT- / OCT+	Reverb throw / echo throw: every send goes full while held, nothing saved
Hold ARP, hold a key	Repeats that note or drum sound in time until released; written as ratchets while recording. Only single notes repeat, even in chord mode
Hold ARP, turn KNOB 1	Roll rate: 1/8, 1/16, 1/32, 1/32 triplet, 1/64
Hold OCT- or OCT+, then ARP and a drum key	Ghost or hard rolls

Mix

Do this	What happens
Hold GLO, white keys 1-4	Mute or unmute tracks 1-4
Hold GLO, white keys 5-8	Solo tracks 1-4 (solos add up)
Hold GLO, white key 9	A fill while held
Hold GLO, white key 10	The next bar plays as a fill (again to cancel)
Hold GLO, white key 16	Tap tempo
Hold GLO, F#3	MIDI LEARN on or off
Hold GLO, turn KNOB 1 to 4	Levels of tracks 1-4
Turn SELECT on TRACKS, in a layer, or while armed	Tempo

Sections and songs

Do this	What happens
Hold SAVE, white keys 1-4	Section A-D takes the place of your working loop: at the next bar while playing, at once when stopped. No question and no undo; in loop mode the loop you had is gone unless you stored it first. Tap several in one hold for a looping chain
Hold SAVE, white keys 5-8	Stores the loop into section A-D. If the section holds a project SLOOP can read (older SLOOP versions included), press the key a second time within 3 s; a section that looks empty is stored over at once
Hold SAVE, white key 13	Loop mode or song mode
Hold SAVE, white key 14	Song recording: the sections you play, from the next bar, replace the song order when it ends
Hold SAVE, white key 16	The SONG screen (its tile on screen says "chain")
SONG screen, KNOB 1 / 2 / 3 / 4	Entry, its section, its length in bars, number of entries. Only the first works while playing
SONG screen, REC / SAVE / OCT- / OCT+	Store the loop into the entry's section, save the song, loop or song mode, load the entry's section (press twice). All need the transport stopped
PLAY in song mode	Plays the song order

Save, load and back up

Do this	What happens
Tap SAVE on a page	SAVE pages: PRESETS, USER, SECTION, TOOLS
PRESETS page, KNOB 1 / 2	Sound; engine (right next, left previous). Either replaces the track’s sound and unsaved edits at once; a running arp keeps playing
PRESETS page, KNOB 4	Right adds the sound to favourites; left removes it. Up to 16 appear before the normal list. A favourite points to a preset or user slot and keeps no edits. Adding one alone does not trigger an idle save; close the HOME menu while stopped to keep it
USER page, KNOB 1 to 4	Slot 1-32, load, erase, save. NO FLASH means the save is unavailable, even for the current powered-on session
SECTION page, KNOB 1 to 4	Section A-D, erase, load, save. Erasing also removes its song-order entries, or creates the default order if none remain. Saving the section again does not recover the removed order
TOOLS page, KNOB 1 / 2 / 4	Clear the pattern, reset the sound, new working loop (stored sections A-D stay; drum tune and decay reset)
Load, save, erase and the tools	One click shows AGAIN; a second turn of the knob within roughly 1.5 s carries it out
While playing	The SECTION page refuses save, erase and load; user-sound save or erase also needs a stop. Nothing is queued. A user sound can still load, and SAVE-layer section calls and stores work during playback; those stores reach flash once stopped and quiet
Leave it alone	The working project saves itself when stopped and idle, and comes back at power-on
Full backup	In the SLOOP web editor: Song & sections, Backup

What overwrites without asking

No question, no undo: SAVE + white key 1-4, at once when stopped and at the next bar when playing (the section replaces your working loop; a chain repeats this as it moves on); SAVE + white key 5-8 on a section that looks empty; song recording (SAVE + key 14) replacing the song order; turning PRESETS, or the PRESETS page's engine knob, over a sound you were editing; a MIDI Program Change doing the same; the autosave.
A second click or press, then no undo: project LOAD, SAVE and ERASE, user sound LOAD, SAVE and ERASE (saving over a used slot gets no further question), TOOLS INIT, SONG screen load (OCT+ twice).
Undo only partly reverses: NEW loop, CLRSQ and holding REC (one track’s notes, length and nudges come back; locks and fill conditions do not).
Loading a song file replaces the working loop, sections A-D and song order after one browser confirmation; tapping a LIVE playlist item or Next does this without another question. A song file is not a full backup.
Restoring a backup asks once in the browser. A backup from 2.5.1 or later without MIDI object 10 resets MIDI settings and learned CCs to defaults. It does not recover device favourites.
MIDI LEARN CLEAR: OCT+ deletes every learned CC immediately, with no second question or undo; the change is saved once quiet.

Before you switch firmware

Back up first. In SLOOP’s USB editor, open Song & sections, then Backup and Save a backup. The SLOOP-backup-<date>.json file holds the working loop, sections A–D and their order, 32 user sounds, the FM6 bank, SYN kits, samples USR1–USR4, the settings (including QUANT and MIDI 3) and a stored custom theme. It omits the device favourite list, browser library, browser scenes and playlist, undo, sounding notes and live drum mutes. Restore asks once in the browser and needs playback stopped; it writes the included objects, with one MIDI exception: a backup from 2.5.1 or later without MIDI object 10 resets MIDI LEARN, track and drum channels, OTHER, BEND and MIDI 3 to defaults. A file without a theme does not erase an existing theme. For a 2.7.1 backup restored onto 2.6, use the 2.7.1 editor: it skips a custom theme the 2.6 unit cannot accept; the 2.6 editor rejects a file containing that theme. Export this song makes a smaller .sloopsong file containing only the loop, sections and order; it cannot replace a full backup before changing firmware.
Back up in the firmware you are leaving first, with its own tool (above). Anything below marked at risk can be written over; whether an older saved copy survives depends on how often you saved, so do not count on it.
What installing SLOOP does to the firmware you had before.
Show the detail
install (loader): SLOOP's update loader writes the program area sector by sector, rewriting only sectors that differ, and verifies each; the flash head (SPL, isd_config) is never written. Nothing is erased before the package's key check (a SLOOP package installed through the update path; refuses to write anything on another flash chip). install (loader): After the write and the host's 'success', the loader erases every 4 KiB sector in 0x93000-0xFBFFF whose last 256 bytes hold a valid update record (rd16 at +6 == 0x5441 and a matching CRC16). Unlike Felucca 1.6's and JIANT's loaders, SLOOP's does NOT skip the data area 0x97000-0xDFFFF (only sectors with a valid update record at offset 0xF00; in practice the staging record sector 0xE4000 (Felucca-family updaters write their record at 0xE4F00)). install (loader): On a first install from the official firmware, the stock update record is expected at 0xE8F00, so the record drop above erases sector 0xE8000 (inside SLOOP's later USR4 range, and Melodee's shared U055-U072 copy B) (only if the stock updater left its record there; the 0xE8F00 location comes from Felucca/JIANT source comments, not from SLOOP's code or the closed stock firmware) [reported]. update: Leaving SLOOP through an update (installer or M-UPGRADE upgrade command, also from USB RESCUE): SLOOP erases the five staging sectors, stages the package's update loader at 0xE0000, then writes the UPDATA_PARM record at 0xE4F00 only after the host confirms 'success'; any failure erases the staging area again. In normal mode it first flushes RAM-only work (sections, pending settings/song, the working project) (an upgrade command from the host; the staged loader must be the official one matching SLOOP's head or a FELUCCA-LOADER-1). update: UPDATE MODE (OCT- + OCT+ held 5 s while stopped, which then enters the chip's USB update mode), the host's UBOOT SysEx and the upgrade command all run persist_flush_now first: dirty sections, a pending settings/song write, and the working project if its hash differs (including the hash-0 case after another firmware's data) (only what is pending; no question). every start-up: ota_boot_cleanup erases all five staging sectors (only if the first 4 bytes at 0xE0000 or the 8 bytes at 0xE4F00 are not blank (0xFF); data elsewhere in the range is not detected). first start-up after another firmware: If SLOOP cannot restore its working loop, it autosaves about 20 s after power-on. With no intact copy it can recognize, its first save writes copy A at 0x9F000, over whatever the previous firmware keeps there: Melodee's shared U109-U126 or Felucca's or JIANT's FM6 user-preset patches. An older intact record can make it use the other copy at 0xFE000 instead (transport stopped, menu shut, 2.5 s without input, nothing sounding). first start-up after another firmware: No settings write happens at start-up itself; but because no settings were loaded (persist_saved zero), the first menu close or any other settings trigger writes the settings even if nothing changed (settings area held a record SLOOP does not accept). first start-up after another firmware: Drum-channel migration on the first start of 2.6 after 2.5: the old project's drum channel is copied into the settings and written once stopped and quiet (settings object of 2.5's exact length and a pre-2.6 working project whose drum channel (0-16) differs from the setting). every start-up: After a warm reset (an update, UPDATE MODE, a crash) a section still valid in .noinit RAM that differs from its flash copy is marked and written back once stopped and quiet (only when RAM survived the reset and differs from flash). install (loader): SLOOP's web installer: no backup and no refusal by firmware identity; it installs over any running firmware that answers the handshake as an FM-1 (model check only), refuses to resume another firmware's update loader ('foreign'), and for the return to official V15 requires the 'backup saved' box and a confirm. It writes nothing to flash beyond the update path above (browser installer at the tag). first idle autosave after an update from 2.6: A restored 2.6 working project acquires the 0x40 saved-by-2.7 marker and drum tuning checksum on capture, changing its hash even with no panel edits. The normal stopped/quiet autosave can therefore commit a new copy (normal stopped/idle autosave guard, no earlier than 20 seconds after boot).
- Stock V15: Possibly at risk (layout reported or inferred): stock settings (and possibly patterns); stock Bluetooth data; stock voices (128 user patches, banks A-D).
- Baud Girl FM-1+VA: Possibly at risk (layout reported or inferred): Baud Girl presets (128); Baud Girl patterns (16, with locks).
- Felucca: At risk by itself: FM6 patches of the FM6 user presets; settings, button calibration, favourites, MIDI LEARN map. At risk when you act: project slot A; project slot B; project slot C; project slot D; the autosave (the music as you left it); FM6 voice bank B1-B32. Carried over: user sample slot USR1; user sample slot USR2; user sample slot USR3. Kept but not shown: user presets 1-16; user presets 17-32.
- X0X: At risk by itself: the whole X0X project (settings, sound, all 32 patterns, song, knob motion). At risk when you act: X0X button calibration. Carried over: break loops slot 1; break loops slot 2; break loops slot 3.
- JIANT: At risk by itself: FM6 patches of the FM6 user sounds; settings, calibration, favourites, MENU options. At risk when you act: song 1 section A (a whole project); song 1 section B (a whole project); song 1 section C (a whole project); song 1 section D (a whole project); song 2: four sections (whole projects); song 3: four sections (whole projects); song 4: four sections (whole projects) (some of it lost); song 5: four sections (whole projects); song 6: four sections (whole projects); song 7: four sections (whole projects); song 8: four sections (whole projects); which song is current, every song's rows and scenes; the music in progress (RESTORE LAST); FM6 voice bank B1-B32. Kept but not shown: user sounds U01-U16; user sounds U17-U32.
- Melodee: At risk by itself: shared user presets U109-U126; settings, factory favourites, calibration, saved template. At risk when you act: shared user presets U289-U378 (some of it lost); shared user presets U379-U384; project A: patterns, song, sounds, motion, recordings; project B: patterns, song, sounds, motion, recordings; project C: patterns, song, sounds, motion, recordings; project D: patterns, song, sounds, motion, recordings; shared user presets U145-U288; shared user presets U073-U090; shared user presets U091-U108; shared user presets U001-U018; shared user presets U019-U036; shared user presets U037-U054; shared user presets U055-U072; shared user presets U127-U144.
- FoMni: At risk by itself: FoMni setup (pages, chord buttons, lights). At risk when you act: FoMni button calibration.
- AMB-1: At risk by itself: AMB-1 pieces and setup. At risk when you act: AMB-1 panel calibration.
- ChoralRoot: At risk by itself: 32 imported DX7 voices; options, playing setup and panel calibration. At risk when you act: CZ-1 bank A (16 tones); CZ-1 bank B (16 tones); CZ-1 bank C (16 tones); CZ-1 bank D (16 tones); CZ-1 bank E (16 tones); CZ-1 bank F (16 tones); CZ-1 bank G (16 tones); CZ-1 bank H (16 tones); last global-save session; favourite marks, chord/bass type and filter; 128 saved sounds with their complete engine patches; recorded loop 1; recorded loop 2; recorded loop 3; recorded loop 4; recorded loop 5; recorded loop 6; recorded loop 7; recorded loop 8; recorded loop 9; recorded loop 10.
- GHOULBOX: At risk by itself: FM6 patches for user sounds; settings and panel calibration. At risk when you act: project A; project B; project C; project D; music in progress (RESTORE LAST); FM6 voice bank B1–B32. Carried over: user sample slot USR1; user sample slot USR2; user sample slot USR3. Kept but not shown: user sounds 1–16 (new GHOULBOX presets show unused; saving into that slot replaces them without an overwrite question); user sounds 17–32 (new GHOULBOX presets show unused; saving into that slot replaces them without an overwrite question).
- M-VAVE FM-1 Open: At risk by itself: Open shared sample audio. At risk when you act: Open USER project 1; Open USER project 2; Open USER project 3; Open USER project 4; Open USER project 5; Open USER project 6; Open USER project 7; Open USER project 8; Open USER project 9; Open USER project 10; Open USER project 11; Open USER project 12; Open USER project 13; Open USER project 14; Open USER project 15; Open USER project 16; Open device preferences. Installing this firmware replaces Open’s sixteen USER projects, preferences and sample header before its first start, including the first 24 KiB of sample storage. This follows Open’s source-defined USER layout and the incoming program range; export projects and device samples before leaving Open.
- FM-106: At risk by itself: octave, last selected preset and MIDI preferences. At risk when you act: older stored user bank, if present (Beta4 does not store new edits). A valid user bank stored by an earlier FM-106 build can still be present and readable in Beta4; the bank risks listed here, if any, apply if it exists. FM-106 Beta4’s new user-sound edits are only in memory: panel save, delete and librarian bank commit do not store them, even when they report success. Read the unit into the librarian and export both user banks before switching or powering off; those exports omit sequence notes, locks and extended controls.
- Hortator: At risk by itself: settings and panel calibration (converted: After this firmware writes its newer settings format, returning to Hortator starts settings, panel calibration and the remembered Bluetooth device from defaults. It does not retry an older copy just because the newest record is too large; settings convert when read; next save writes a newer format the previous firmware cannot import). At risk when you act: project A; project B; project C; project D. Carried over: user samples USR1 (sample loop and slice behaviour follow this reader’s engines); user samples USR2 (sample loop and slice behaviour follow this reader’s engines); user samples USR3 (sample loop and slice behaviour follow this reader’s engines).
- OberVave: At risk by itself: pattern 1 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); pattern 2 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); pattern 3 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); pattern 4 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); pattern 5 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); pattern 6 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); pattern 7 (its B-track sound can change if it uses a saved program; its pattern notes remain; other writes can also erase it); saved programs and global settings; pattern 8 (its B-track sound can change if it uses a saved program; its pattern notes remain).
- Polly: At risk by itself: Polly shared memory 4; Polly setup and channel sounds. At risk when you act: All four Polly songs; Polly shared memory 1; Polly shared memory 2; Polly shared memory 3; Polly shared memory 5; Polly shared memory 6; Polly shared memory 7; Polly shared memory 8; Polly shared memory 9; Polly shared memory 10; Polly shared memory 11; Polly shared memory 12; Polly shared memory 13; Polly shared memory 14; Polly shared memory 15; Polly shared memory 16; Optional QY70 style bank; Polly button and encoder calibration.
- Skiff: At risk by itself: user sounds’ own FM6 patches; user sound bank 1 (only FM6 sounds can lose their own patches and fall back to a factory patch or the initial voice; other sounds remain; other writes can also erase it); user sound bank 2 (only FM6 sounds can lose their own patches and fall back to a factory patch or the initial voice; other sounds remain; other writes can also erase it); settings, calibration and favourites. At risk when you act: project A; project B; project C; project D; last session; shared 64-pattern pool. Carried over: user sample USR1 (sample loop and slice behaviour follow this reader’s engines); user sample USR2 (sample loop and slice behaviour follow this reader’s engines); user sample USR3 (sample loop and slice behaviour follow this reader’s engines).
What the next firmware does to SLOOP's data.
- Stock V15: Possibly at risk (layout reported or inferred): song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave); user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000); user sounds U01-U16; user sounds U17-U32; FM6 patch bank B1-B27; user sample slot USR4 (header at 0xE7000).
- Baud Girl FM-1+VA: Possibly at risk (layout reported or inferred): song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave); user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000); user sounds U01-U16; user sounds U17-U32; FM6 patch bank B1-B27; user sample slot USR4 (header at 0xE7000).
- Felucca: At risk by itself: FM6 patch bank B1-B27; settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk by itself, under a condition: user sample slot USR4 (header at 0xE7000). At risk when you act: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave); user sounds U01-U16 (converted when read, written back at your next save in that bank); user sounds U17-U32 (converted when read, written back at your next save in that bank). Carried over: user sample slot USR1 (header at 0xA0000) (new SLOOP LOOP / LOOP+TAIL samples play as ordinary loops here); user sample slot USR2 (header at 0xB4000) (new SLOOP LOOP / LOOP+TAIL samples play as ordinary loops here); user sample slot USR3 (header at 0xC8000) (new SLOOP LOOP / LOOP+TAIL samples play as ordinary loops here).
- X0X: At risk by itself: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); user sounds U17-U32; settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk when you act: user sounds U01-U16. Carried over: user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000).
- JIANT: At risk by itself: user sample slot USR3 (header at 0xC8000); settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk by itself, under a condition: FM6 patch bank B1-B27; user sample slot USR4 (header at 0xE7000). At risk when you act: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave); user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sounds U01-U16 (converted when read, written back at your next save in that bank); user sounds U17-U32 (converted when read, written back at your next save in that bank).
- Melodee: At risk by itself: the music in progress (autosave); user sounds U01-U16; user sounds U17-U32; settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk by itself, under a condition: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); user sample slot USR3 (header at 0xC8000); FM6 patch bank B1-B27; user sample slot USR4 (header at 0xE7000). At risk when you act: user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000).
- FoMni: At risk by itself: settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk when you act: user sounds U01-U16.
- AMB-1: At risk by itself: settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk when you act: user sounds U01-U16.
- ChoralRoot: At risk by itself: user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000); settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk when you act: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave); user sample slot USR1 (header at 0xA0000); user sounds U01-U16; user sounds U17-U32.
- GHOULBOX: At risk by itself: FM6 patch bank B1-B27; settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk by itself, under a condition: the music in progress (autosave); user sample slot USR4 (header at 0xE7000). At risk when you act: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); user sounds U01-U16 (converted when read, written back at your next save in that bank; all bank records are rewritten after in-RAM migration; firmware-specific sounds can differ); user sounds U17-U32 (converted when read, written back at your next save in that bank; all bank records are rewritten after in-RAM migration; firmware-specific sounds can differ). Carried over: user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000).
- M-VAVE FM-1 Open: At risk by itself: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave). At risk when you act: user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000); user sounds U01-U16; user sounds U17-U32; FM6 patch bank B1-B27; user sample slot USR4 (header at 0xE7000); settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. The factory-sample write runs by itself right after the Workbench installs Open, before any project save. The source-built V12 bank erases 0x8D000–0x9FFFF without another sample question. The shipped Workbench asset was not compared with the source.
- FM-106: At risk by itself: settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites.
- Hortator: At risk by itself: settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk when you act: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project). Carried over: user sample slot USR1 (header at 0xA0000) (Sample bytes remain on the unit; playback follows Hortator’s one-shot engines, so loop and slice behaviour can differ. Valid header and zone bounds are required; no unit switch was tested); user sample slot USR2 (header at 0xB4000) (Sample bytes remain on the unit; playback follows Hortator’s one-shot engines, so loop and slice behaviour can differ. Valid header and zone bounds are required; no unit switch was tested); user sample slot USR3 (header at 0xC8000) (Sample bytes remain on the unit; playback follows Hortator’s one-shot engines, so loop and slice behaviour can differ. Valid header and zone bounds are required; no unit switch was tested).
- OberVave: At risk by itself: user sample slot USR4 (header at 0xE7000) (damaged (part of it written over)); settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites.
- Polly: At risk by itself: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave); user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk by itself, under a condition: user sample slot USR4 (header at 0xE7000). At risk when you act: user sample slot USR3 (header at 0xC8000); user sounds U01-U16; user sounds U17-U32; FM6 patch bank B1-B27.
- Skiff: At risk by itself: FM6 patch bank B1-B27; user sample slot USR4 (header at 0xE7000); settings, calibration, song order, SYN1-4 kits, MIDI LEARN, theme and favourites. At risk by itself, under a condition: song section A (a whole project); song section B (a whole project); song section C (a whole project); song section D (a whole project); the music in progress (autosave). At risk when you act: user sounds U01-U16 (converted when read, written back at your next save in that bank); user sounds U17-U32 (converted when read, written back at your next save in that bank). Carried over: user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000).
Who reads whose data.
Show the detail
Other firmwares reading SLOOP's data: Felucca lists SLOOP's user sounds U01-U16; user sounds U17-U32; user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000), but plays them differently (new SLOOP LOOP / LOOP+TAIL samples play as ordinary loops here); X0X reads and uses SLOOP's user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000); JIANT lists SLOOP's user sounds U01-U16; user sounds U17-U32, but plays them differently; ChoralRoot lists SLOOP's user sounds U01-U16; user sounds U17-U32, but plays them differently (legacy records may be copied, but retired/renumbered engines and foreign deep patches change their sound; confirmed Flash Data still erases the sources); GHOULBOX lists SLOOP's user sounds U01-U16; user sounds U17-U32, but plays them differently (all bank records are rewritten after in-RAM migration; firmware-specific sounds can differ); GHOULBOX reads and uses SLOOP's user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000); Hortator reads and uses SLOOP's user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000) (Sample bytes remain on the unit; playback follows Hortator’s one-shot engines, so loop and slice behaviour can differ. Valid header and zone bounds are required; no unit switch was tested); Skiff reads and uses SLOOP's user sounds U01-U16; user sounds U17-U32; user sample slot USR1 (header at 0xA0000); user sample slot USR2 (header at 0xB4000); user sample slot USR3 (header at 0xC8000). What SLOOP reads of other firmwares' data: SLOOP reads and uses Felucca's user sample slot USR1; user sample slot USR2; user sample slot USR3; SLOOP reads and uses X0X's break loops slot 1; break loops slot 2; break loops slot 3; SLOOP reads and uses GHOULBOX's user sample slot USR1; user sample slot USR2; user sample slot USR3; SLOOP takes over Hortator's settings and panel calibration, converting them (settings convert when read; next save writes a newer format the previous firmware cannot import); SLOOP reads and uses Hortator's user samples USR1; user samples USR2; user samples USR3 (sample loop and slice behaviour follow this reader’s engines); SLOOP reads and uses Skiff's user sample USR1; user sample USR2; user sample USR3 (sample loop and slice behaviour follow this reader’s engines). Everything else of another firmware's looks empty or foreign to the reader.
Every way each write can happen, for all mapped firmwares: the flash atlas's table. Read in each firmware's source (closed ones: their docs or third-party reports); nothing was tested on a unit.

Updating from SLOOP 2.6 keeps the song, working loop, user sounds, samples, SYN kits and settings. Projects still use FUN6, and the new drum TUNE and DECAY travel with each section. The extra theme and favourite data share the settings sectors; they do not claim a new flash area.
The official firmware cannot open SLOOP’s music or samples. A 2.7.1 project opens in 2.6, but its new arp modes, KBD HOLD and per-drum TUNE/DECAY do not play the same; held-note overdubs and looping samples can also sound different. A settings save in 2.6 drops MIDI 3, newer setting bits, the custom theme and device favourites. A 2.7.1 backup still needs 2.6 or later for FUN6 projects; the current editor refuses an older target before writing. The editor’s sound library, scenes and playlist live in the browser. Device favourites are absent from its backup. Going back to 2.5 with changed MIDI channels, OTHER, BEND, any MIDI 3 value or a learned CC makes its SYN kits start from defaults; its next settings save loses the saved kits and MIDI part.

Lights

PLAY flashes on the beat. REC blinks when armed, stays lit while recording, blinks fast while the clear ring fills. The button of the page or layer on screen is lit, and blinks when its layer is locked. OCT- and OCT+ are lit while the keyboard is shifted away from octave 0 (synth tracks), while held (drum track), or during a throw (FX layer). Keys 1, 5, 9 and 13 stay faintly lit as row markers whenever a layer is held, and all the time on the drum track.

Do this	What happens
Hold HOME 0.7 s	Opens the menu; hold again (or OCT-) to close
In the menu, SELECT / PRESETS / KNOB 1-4	Section / cursor / set each row
In the menu, OCT+	Cycles the setting or opens calibration or ABOUT. On MIDI LEARN CLEAR it deletes all learned CCs at once, with no confirmation or undo, and saves once quiet
Menu sections	SCREEN (colour or custom theme, zoom, knob acceleration), LIGHTS (button glow, key glow, played-note lights), AUDIO (speaker low cut, USB audio level, USB rate), SYSTEM (second core, calibration, MIDI LEARN clear, ABOUT). USB SERIAL appears only in console-enabled builds
Fast knob turns	Numeric values sweep farther as the turn speeds up. SCREEN > KNOB ACCEL OFF gives one value per click; named choices do not accelerate
SCREEN, COLOR	Built-in palettes, then your installed custom theme. Make the theme in the web editor
AUDIO, USB RATE	AUTO, 44.1 kHz or 48 kHz; restart to apply
SYSTEM, 2ND CORE	OFF changes to one-core rendering immediately. ON can reuse a core that started successfully; otherwise another power-on is needed. A late second-core job also forces one-core use until another power-on
Menu screen	SYSTEM has ABOUT in its fourth row instead of a help reminder. RESTART marks USB changes awaiting a restart; NOT RUNNING marks an unavailable core. ABOUT can show 2 CORES, 1 CORE or C1 OFF

MIDI and the browser editor

Do this	What happens
GLO > MIDI 3, KNOB 1 / 2 / 3 / 4	FX CH, DR MAP, REMOTE, CLOCK
FX CH	Notes F3-G5 on that channel hold punch-in effects, unless MIDI IN is CLOCK
DR MAP	GM keeps the drum-note map; 1-16 starts with KICK at note 36 and repeats the sixteen sounds across the MIDI note range
REMOTE	On its chosen channel: 102 FX, 103 SEL, 104 ENV, 105 LFO, 106 EDIT, 107 GLO, 108 HOME, 109 SAVE, 110 ARP, 111 SEQ, 112 PLAY, 113 REC, 114 OCT-, 115 OCT+. Values 64-127 hold; 0-63 release
Before unplugging TRS MIDI	Release remote buttons, set REMOTE OFF or change its channel. Pulling TRS does not release them; a stuck REC can clear a track. USB loss does release remote buttons
Incoming CC74	Sets the engine cutoff where available, otherwise the track FILTER; MIDI LEARN takes priority
CLOCK OUT	With internal sync, sends USB MIDI clock plus start/stop
Browser editor	LIVE controls performance, throws and levels; Song & sections saves or loads a song file; playlists replace the working song when selected

Power-on and rescue

Do this	What happens
Switch on holding OCT-	USB rescue: audio off, waiting for a reinstall from the browser. It also starts by itself after two failed starts
Switch on holding OCT- and OCT+	Hardware calibration: press each named button, turn each named knob right
Hold OCT- and OCT+ 5 s while stopped	Your work is saved and the FM-1 enters update mode. The screen counts down after 2 s; releasing either button stops it

Where the docs and the firmware disagree

Which pages each button opens. The 'every button, alone' table lists LFO as LFO and LFO DEST, FX as five pages, EDIT as four and GLO as four (GLOBAL, MASTER, SYSTEM, DRUMS). The page table includes LFO 2, INSERT and INSERT 2, ANALOG-only FILTER under EDIT, and nine GLO pages including MIDI, MIDI 2, MIDI 3, TEXTURE and TEXTURE 2. SAVE now calls its slot page SECTION. The guide’s detailed sections have these changes; its overview tables lag behind.
Going back to an older SLOOP. The guide's install section warns only that 2.3 cannot read 2.4 projects (format FUN5), and its backup section says a 2.4 backup restores into 2.4 or later. 2.7.1 still writes FUN6, introduced in 2.6, which 2.5 cannot read. The editor checks project formats before restoring. Its projects open in 2.6 with limits on the new 2.7 features; README and SLOOP.md explain this, while this GUIDE warning is still about 2.4.
SAVE layer, white key 16. SAVE + key 16 opens the SONG screen. It does, but the layer screen labels that tile 'chain', which can mislead: chains are made with keys 1-4.
ARP note repeat in chord mode. The ARP layer repeats the held key; chord mode plays a whole chord from one key. The guide does not say which a roll repeats in chord mode. A roll always repeats the key's single (root) note, never the chord; and on a synth track black keys are silent in chord mode, so they roll nothing.
Pages that work on the drum track. On the drum track the pages that work are SLICER, PATTERN, the SONG screen and the global pages. INSERT and INSERT 2 also work on the drum track (the guide's effects section agrees), and so does the TRACKS screen.
OCT- and OCT+ lights. OCT- and OCT+ light when the octave is off 0. Only on a synth track. On the drum track they light only while held (ghost or hard hits), and inside the FX layer they show the reverb and echo throws.
Undo after clearing a track. Holding REC clears the selected track and undo brings it back. Clearing also deletes parameter locks, nudges and fill conditions. Undo in 2.7 restores notes, pattern length and nudges, but it still has no snapshot of the locks or fill conditions.
DRUMS page overview. The button and SELECT overviews describe switching between grid and kit only. There are three pages: GRID, KIT and SOUND. EDIT or SEQ cycles through them; SELECT moves within the three-page range. The guide’s detailed DRUMS section already describes SOUND.
Theme record in the editor protocol. The v11 protocol section describes a 36-byte THM1 record without a separate accent colour. The current record is 40-byte THM2 and includes the accent and its CRC. A 36-byte THM1 from the beta is accepted and converted.
Saving device favourites. The guide says the device favourites survive power-off. A favourite edit does not trigger an idle save by itself. It needs another action that writes settings; closing the HOME menu while stopped commits it. Device favourites are not in an editor backup.
When 2ND CORE OFF applies. The release notes say disabling the second core takes effect after another power-on. OFF stops assigning work to that core immediately. ON can resume it immediately only if it started successfully; otherwise another power-on is needed.
Where to find Backup. The guide sends the owner to an editor tab named Projects for Backup. The tab is now named Song & sections; its Backup buttons are in that panel.

Mapped from isod89/sloop-fm1 at v2.7.1 (4ec1ac8), 2026-10-16. Behaviours were read in source, not tested on a unit; the sources are in sloop.json. SLOOP is GPL-3.0-only, by isod89 (3dSam), built on Felucca by Leo Kuroshita (Hügelton Instruments). This is an independent guide written in our own words, not affiliated with SLOOP, Felucca or M-VAVE. M-VAVE and FM-1 belong to their respective owners as trademarks.

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