Dreamy_bacon's LSDJ Burrito

LSDJ Burrito runs your own copy of Little Sound Dj on an M-VAVE FM-1, with GameDude-based firmware (the source is in lsdj-burrito-src). This repository is its web page.

With LSDJ Burrito running on the FM-1 (alpha 55 or later), connected by USB, the page talks to the running firmware over USB-MIDI (Chrome or Edge, MIDI with SysEx allowed). Firmware installation is a separate, explicitly confirmed action.

• The FM-1's screen (FM-1_983 and newer): above Effects, exactly as its display shows it, effects panels included. View only; only the parts that changed are read again, and nothing is read while it is folded away or another tab is shown.
• Live effects: every channel's effects and the echo, following the FM-1 as you play; move a slider to change it on the FM-1, keep the setup on the FM-1.
• Songs: export the FM-1's songs as lsdj.sav, import a 128 KiB .sav (the FM-1 keeps its songs if an import fails).
• Colours: make a custom theme from a preset with a preview, send it (THEME: CUSTOM on the FM-1).
• Settings: change them, back up settings + effects + colours to a file, restore it.
• Prepare firmware: use your own LSDj ROM and explicitly choose its sample kits, entirely in the browser.

The section shortcuts distinguish physical-device controls from local firmware tools. After preparation, links take you to the download, local preview or USB installer; navigating never starts emulation or installation. Virtual FM-1 shows the selected package's name and disables its selected-package preview button while no package is available or preparation is in progress. Changing that selection does not replace an already running virtual machine.

USB Connect and Install are disabled with an explanation when Web MIDI is absent or the page is not a secure context (HTTPS/localhost). This checks browser API availability, not device presence or permission. ROM preparation/download still work on secure browsers without Web MIDI; emulator support has its own WebGL, WebAssembly and audio requirements below.

Master and channel effects (FM-1_977 and newer)

Effects shows a Master box first: the MASTER page (on the FM-1, tapping FX opens the effects panel on it, until FX again) and PU1-NOI mute buttons (lit = playing; the same mutes as C4-F4 on the FM-1's master pages and MIDI CC 81, sent with link op 0x24 MUTE_SET, live only). Freeze is settable from the page too. Channel effects and echo follow below with FILTER, DRIVE, LFO, LO-FI, ECHO and ECHO MOD (977 had the echo pages in Master; 978 moved them back). The FM-1 page indicator follows the live page, including the master pages while the FX panel shows them, without changing the saved channel page. Older firmware shows the mutes but cannot be set from here.

FX organization (FM-1_975 and newer)

The first card/device page is MASTER: K1 All FX switches channel DSP, shared echo and compressor on/off together; K2 Compressor is shared by all channels. All FX off keeps the original dry mix and channel mutes without erasing any settings. It is independent of the cursor and the channel chosen on the webpage. SAVE/Keep and 17-word settings backups retain the switch.

The remaining pages match the device knobs:

Page	K1	K2	K3	K4
1 MASTER	All FX	Compressor	Echo mix	Echo time
2 FILTER	Channel FX	Echo send	Cutoff	Resonance
3 DRIVE	Drive	Distortion	Warmth	-
4 LFO	Rate	Depth	Shape	Destination
5 LO-FI	Crush	Decimate	Filter type	-
6 ECHO	Time	Feedback	Mix	Tone
7 ECHO MOD	Wobble	Sync	Mode	Freeze

This is FM-1_980 and newer (MASTER K3/K4 since 980; echo send on FILTER K2 and filter type on LO-FI K3 since 979). SELECT changes the device page. Unused knobs do nothing. ECHO and ECHO MOD are shared; FILTER/DRIVE/LFO/LO-FI edit the chosen channel. Freeze is ECHO MOD K4 on the FM-1, and settable from the page (977 and newer). Older connected firmware retains its original page/knob layout, with an explanation that All FX needs 975 or newer. New-layout backups cannot be restored to older firmware. Both 11-word and 17-word legacy backups remain accepted on supporting firmware.

This does not resolve the reported physical cursor-following failure; hardware diagnosis is still pending.

Importing saves with extra bytes

Raw LSDj saves are 131072 bytes. For a 131088-byte file (such as the reported LSDj Patcher export), the importer offers an explicit warning and confirmation to use only the first 131072 bytes, excluding the final 16. The extra bytes' format is not verified: this option is not suitable for a file with a leading header. Cancelling sends nothing. Your original file is never modified; the USB save protocol still accepts exactly 131072 bytes. Other file sizes are rejected. Back up the FM-1's songs before replacing them, and use the matching LSDj version.

Run node tests/save-import.mjs for confirmation, cancellation, byte-preservation and simulated transfer checks. Optional local save-file paths test the same conversion without writing any files or contacting a device.

Experimental multi-version loader

1. Back up songs and settings before changing firmware or LSDj versions. Save compatibility between versions is not guaranteed.
2. Choose your own .gb file under Prepare firmware. The page checks its LSDj title, MBC5 mapper, size, 128 KiB RAM requirement and header checksum. GBC-only and rumble cartridges are refused.
3. All recognized sample kits start selected. The ROM-free FM-1_976 template holds 31 banks plus a 256-byte header (508,160 bytes). A typical ROM with 13 required program/data banks leaves 18 kit banks. If necessary, deselect kits yourself; the page never silently removes them. Unknown data and zero-filled banks remain mandatory. Some modified ROMs cannot fit even with no kits.
4. Kit bank numbers and retained sample bytes are preserved. Songs referring to omitted kits lose those samples. The global ROM checksum is recalculated for the sparse image.
5. Read the experimental/backup acknowledgement, then choose Prepare firmware. Template hashes, protected firmware, loader, slot mapping and package CRCs are checked before and after insertion.
6. Download the private .fwsc for M-UPGRADE, or use the separate USB installer. Preparing or downloading does not write to a device. Changing ROM options invalidates the generated installer selection.

The preparation status explains the next step and why the button is disabled. If kits exceed the budget, it reports how many kit banks you must deselect. If the required program/data alone exceeds capacity, removing kits cannot help; choose a smaller compatible ROM instead. Files with no recognized kits retain all required data. Invalid ROM headers are rejected before fetching the catalogue or template. Failed file checks allow selecting the same file again; a later file selection takes precedence over an earlier read or template request. Installer file errors are shown explicitly and clear the invalid selection.

FM-1_976 uses the verified LSDj 9.3.9 profile for matching program code, including custom or omitted sample kits. The browser compares the program SHA-256, not the title, and writes a cursor profile into the CRC-protected slot header. The firmware uses it to read the cursor channel and, since FM-1_976, for every 9.3.9 helper: SEQ live / song mode, EDIT tempo, ARP song cues, MIDI clock / KEYBD sync and the PLAY beat light (975 and earlier used only the cursor, so SEQ did nothing in web builds). Unknown programs use ALL-channel FX, explicitly reported before and after preparation. Theme-accent bars, meaningful segments, choice selectors and CPU1 save fixes remain unchanged. The identity is newer than 973; normal alpha 71 builds are unchanged.

The template is not hardware-validated. Version-specific tempo shortcuts, MIDI clock integration and song cues remain disabled. An exact ROM hash or matching program fingerprint is evidence of identity, not proof of complete firmware/ROM compatibility. Other structurally valid LSDj versions remain experimental. The user reported successful webpage flashing of 972 but loss of cursor-following; 973 corrects that behavior for the verified program.

Updating from the installed LSDj

One-time bootstrap: firmware 973 and earlier cannot export their cartridge. Use your original ROM once to prepare and install 974 or newer, then reconnect. Normal private non-slot builds do not advertise cartridge export either.

For subsequent supported updates:

1. Back up songs and settings separately. Connect to the running FM-1.
2. Choose Read installed LSDj (no device writes). A progress bar and Cancel button are available; reading may take several minutes over MIDI.
3. The page verifies the transferred slot and loads the latest template. All currently installed kit banks are retained and locked. Missing banks remain FF; previously omitted samples cannot be recovered from the device.
4. Accept the experimental/backup acknowledgement and choose Prepare firmware.
5. Download or preview the private package, then explicitly choose Install.

Reading never writes firmware, pauses LSDj or backs up songs/settings. Data stays in browser memory, is not uploaded or persisted, and is discarded on reload. This updates Burrito around the existing LSDj; changing LSDj itself still needs a newer ROM. If the installed cartridge cannot fit a future template, the page refuses preparation rather than dropping kits. Use the original-ROM path to choose different kits explicitly.

The read-only protocol uses CART_INFO (0x22) and offset-echoed CART_READ (0x23, 120-byte chunks). Timed-out reads retry; stale-offset replies are ignored; short chunks, checksum/layout failures and changed cartridge metadata fail explicitly. Cancel/disconnect releases the request and restores controls. Preparation/installation and physical controls are locked during the read. Old firmware gets bootstrap guidance, not a save-memory fallback.

Run node tests/device-update.mjs for synthetic transfer/failure tests. Optional private ROM arguments compare device-readback preparation with the original-ROM package byte-for-byte, including kit numbering and cursor profile. For the actual C protocol bridge, compile source tests/lsdj_cartridge_link.c with gcc -std=c99 -O2 -Ifirmware -Isrc ... and set LSDJ_CARTRIDGE_LINK to that executable when running the Node test. Private temporary slots are removed. On a fresh localhost page, run await (await import('./tests/loader-ui.mjs')).runDeviceUpdateUiTests() for mocked-MIDI UI checks. This suite never contacts a physical device.

Flashing risk: an earlier interrupted web install left an FM-1 unable to start. Keep stable power, the cable connected and this tab open/in front. Simulated transfer/retry tests and package integrity checks do not guarantee physical recovery. M-UPGRADE is an alternative transport, not proof that an experimental image is safe.

ROMs and samples stay local. The checked-in template contains an erased ROM window only. Generated firmware contains your ROM: keep it private and do not commit or publish it.

The template's matching firmware source archive includes build instructions, licenses and a per-file source manifest. It contains no LSDj ROM or save. Rebuilding this archive reproduced the published template and metadata byte-for-byte. Archive SHA-256: a6b1af73c28c92870604c94133f931c94a6596a5e186dbe3a70fe1811068862d.

Local preview and checks

Virtual FM-1 (3D)

The Virtual FM-1 section executes the actual .fwsc firmware on Joakim Eriksson's FM-1 emulator, not just the embedded Game Boy ROM. Choose a local package and Start, or use Preview selected installer firmware for the package prepared/selected above. This captures a separate copy; later installer selection changes do not replace an already running virtual machine.

The emulator and Three.js assets are served locally and loaded on demand. No private packages are uploaded, no hosted emulator iframe is used, and this section never requests MIDI access or writes a physical device. The live Songs, Settings and Effects sections still target the physical FM-1, not the emulator.

Click keys, drag/scroll knobs, or focus the 3D instrument and use arrows, Z/X and Shift/Enter for the firmware's Game Boy direction, B/A and Select/Start keys. The mapping follows Burrito; other firmware may assign those keys differently. Press X (A) to leave LSDj's first-boot cartridge test once it finishes. Front view and tilt/turn controls adjust the 3D camera view; Enlarge screen shows a readable LCD alongside it. Pause retains the virtual machine; Stop/restart/reload discards all virtual songs/settings, even changes saved through the simulated firmware. There is no browser persistence or raw .sav import into the emulator in this version. Export/import above remains a physical-device operation.

WebGL2, WebAssembly/JIT and AudioWorklet support are required (current Chrome/Edge, HTTPS or localhost). Audio starts only after an explicit Start. Switching tabs pauses emulation. Starting a physical firmware install stops the emulator to free resources. The default 240 MHz is the hardware clock; lower choices deliberately underclock the simulation. Watch the real-time/short-buffer counters: running a Game Boy emulator inside an FM-1 emulator is expensive. Successful emulation is not a hardware flashing/recovery guarantee or proof of accurate audible playback. Alpha 66 and generated FM-1_967 packages passed headless CPU/display tests; the 967 runtime also passed a 15-second headless run. Both packages reached LSDj's song screen in the 3D view. Browser tests measured below real-time here (about 50-90%). One VS Code embedded-browser tab crashed during testing; a fresh tab subsequently passed a 50+ second emulated 967 run, pause/resume and 3D key/knob checks. That crash is unresolved, so this remains an experimental preview, not a stable audio-production tool.

The FM-1_975 template passed local package-generation and 15-second firmware-emulator checks with LSDj 9.3.9: 661376 audio frames, LCD output, input accepted and CPU not halted. Its erased cartridge window and matching source-archive rebuild were verified. These checks do not validate physical flashing, audible fidelity or save compatibility. The earlier 974 generated-slot host test moved the real ROM cursor through channels 0/1/2/3/2/1/0 and verified cutoff edits affected only that channel; its private SONG-screen fixture was not available for the 975 rerun. Existing rendering tests still confirm no channel tint across all 92 themes.

The 975 FX tests additionally verify bit-exact global bypass with channel mutes, preserved settings, advancing echo/LFO/compressor state, seven-page mappings, inert unused knobs, legacy page migration, and USB settings round trips. Browser checks cover All FX independently of the selected channel, live device state, 11/17-word backups, older-firmware gating and overflow-free controls at 320/390/820/1280-pixel widths.

For that cursor regression, compile the source repository's tests/lsdj_rom.c with src/gb_port.c, build/minigb_apu.c, -Isrc -Ifirmware -Ivendor/peanut-gb, -DMINIGB_APU_AUDIO_FORMAT_S16SYS -DAUDIO_SAMPLE_RATE=44100 -UNDEBUG and -lm. Run tests/loader.mjs with a private 9.3.9 ROM argument and environment variables LSDJ_SLOT_SMOKE (compiled test path) and LSDJ_CURSOR_SAVE (a private, exact 128-KiB save that starts on the SONG screen). No save is modified or published.

Upstream source revision, deployed WASM provenance, versions and asset hashes are pinned in emulator/upstream.json. The WASM was obtained from upstream's deployed page, not rebuilt here; source is MIT-licensed. The worklet/JIT are unchanged upstream files. Retain both MIT license files under emulator/vendor/ when distributing. The 3D shell and Burrito integration are local additions; the live panel artwork/hit testing comes from the emulator.

Run node tests/emulator.mjs for asset integrity, package and runtime checks. Optional .fwsc arguments execute local packages with the actual FM-1 emulator; optional .gb arguments prepare an experimental package in memory and test it. Tests select fitting kits explicitly and do not save ROM-bearing packages.

Serve this repository on loopback, for example python -m http.server 8891 --bind 127.0.0.1, and open http://localhost:8891/ in Chrome or Edge. Loading directly from file: is not supported.

For browser UI regressions, open a fresh local preview with the browser cache disabled, then run this in its developer console:

await (await import('./tests/loader-ui.mjs')).runLoaderUiTests()

This uses synthetic files and simulated network failures to check visible errors, same-file retries, file-selection races, capacity guidance, consent and stale download/installer invalidation. It never connects to or installs on a device. It changes the form selections; reload afterward to discard the test state. The suite also checks navigation targets and selected-package preview state. On a fresh localhost page in a browser without Web MIDI, run await (await import('./tests/loader-ui.mjs')).runUnsupportedMidiUiTests() to check disabled USB controls, early rejection before install confirmation and continued local preparation/download/preview selection. This test does not start the emulator or access a device.

Run node tests/fx-model.mjs for FX format/layout tests (the FM-1_979 knob layout and the 975-978 one, the FX+LIGHTS feature switches, the complete MIDI CC map), node tests/fx-diagram.mjs for the Effects tab's wiring diagram, node tests/zip.mjs for the Export all archive and node tests/screen.mjs for the screen mirror (lsdj/screen.js). On a fresh local preview, run await (await import('./tests/fx-ui.mjs')).runFxUiTests() for simulated MIDI controls and backup compatibility, and .runExportUiTests() from the same module for the Songs tab's effects export and Export all .zip; reload afterward to remove the mock connection. tests/fx-shot.mjs only connects a pretend FM-1_979 for screenshots and the narrow-screen check.

From FM-1_979 the Songs tab exports the songs (lsdj.sav), the installed LSDj read back from the FM-1 (lsdj-installed.gb, web installs from FM-1_974) and the effects (lsdj-burrito-effects.json) separately, or all three as separate files in one .zip. These go to the user's own computer only; nothing ROM-bearing is published.

Run node tests/loader.mjs with Node 22+ for synthetic ROM, sample selection, slot, protected-template, package and simulated transport regressions. Optional positional arguments are local ROM paths; these test package round trips without saving ROM-bearing packages. With LSDJ_SLOT_SMOKE set to the firmware's compiled tests/lsdj_rom.c executable, they also test each generated slot with the emulator for 600 frames. This is not an audible sample or hardware test.

Rebuild the ROM-free assets using the firmware repository's tools/lsdj_template.py (see its README), then copy only its verified empty template and matching metadata into lsdj/. Never replace the template with a generated user-ROM package. When updating the template, also replace its matching source archive, verify the rebuild, and update the archive checksum above. Do not include ROMs, saves, private calibration, build outputs or credentials in the source archive.

Licenses

• This page is GPL-3.0-only (see LICENSE).
• The firmware (in lsdj-burrito-src) contains Peanut-GB and MiniGB APU (MIT), Felucca (GPL-3.0-only) and JieLi AC79 SDK boot files (Apache-2.0). See licenses/.
• The optional virtual FM-1 runtime and Three.js are MIT-licensed; see emulator/vendor/LICENSE-fm1-emu.txt and emulator/vendor/LICENSE-three.txt.

Not affiliated with M-VAVE, Johan Kotlinski (LSDj) or Nintendo.