midisc — 1.40MIDISC5

ColdFire patch that adds MIDI scene locks to official Octatrack OS 1.40C.

There is no prebuilt firmware in this repo. You rebuild from your own 1.40C (same extract → patch MAIN OS → repack path used by octabam-style tooling).

Behaviour

• MIDI track scene A/B locks + XF morph between scenes
• Locks survive Part Save → reboot (sparse persist in the part window)
• Part Copy/Paste/Clear + Part Reload midisc; project save/reload keeps locks (all parts)
• Bank load keeps machine regs (1.40C sample load stays intact)
• Site B bank publish does not pack (avoids durable SAVE mid bank-load)
• Full scene B: CTRL CC locks stay frozen on dial (CC_TX uses mixed VOICE)
• Solid green scene-lock LEDs (no blink path)
• ARP scene-lock values clamped to real knob ranges

Technical map: docs/TECH.md. Constants: tools/midisc/memory_map.py.

Rebuild from stock 1.40C

Requirements: Python 3. Your own official 1.40C (never commit/share it).

# 1) Obtain stock (optional helper)
powershell -ExecutionPolicy Bypass -File scripts/fetch-os.ps1   # or scripts/fetch-os.sh

# 2) Patch MAIN OS + repack flash image
python tools/build_midisc40.py

Pipeline inside the build:

1. ensure_stock() — use out/raw/section_3_MAIN_OS.bin if present, else extract from downloads/extracted/OCTATRACK_OS1.40C.syx
2. Assemble caves/stubs (tools/midisc/*.py + ot3_asm.py) and splice hooks
3. tools/repack_140fx.py → Desktop 1.40MIDISC5.bin (splash 1.40MDISC5, ≤10 chars) (+ syx under out/)

Then flash that build’s .bin (CF root → OS UPGRADE). Details: docs/FLASHING.md.

Sources

path	role
tools/midisc/build.py	place code, patch sites, call repack
tools/midisc/hold.py	A/B hold store, dial, unlock, ARP clamp
tools/midisc/parts.py	pack/unpack, save/reload, bank preserve, after-project-load
tools/midisc/morph.py	XF mix / morph / plock / write remix + VOICE→d2
tools/midisc/scene_ui.py	clear / copy / paste
tools/midisc/emit.py	shared MSC helpers
tools/midisc/memory_map.py	all 1.40C addresses
tools/ot3_asm.py	ColdFire assembler
tools/extract_main_os.py	syx → MAIN OS
tools/repack_140fx.py	MAIN OS → .bin / .syx
tools/syx_elektron.py, aplib_elektron.py	ELEK container

⚠️ Safety

Modified OS can brick the unit; not affiliated with Elektron; flash at your own risk. Do not share built .bin / .syx (they contain Elektron’s OS). Share this repo; everyone builds from their own 1.40C.

Octatrack / Elektron — trademarks of Elektron Music Machines MAV AB.

License

MIT for this repo’s code and docs. Not for Elektron firmware.