| name | sp-1 |
| description | This skill should be used when the user asks about the Teenage Engineering SP-1 stem player (or "Stem Player SP-01"), the nRF52840-based Kanye/TE collaboration device, custom firmware development for it, custom stems / album encoding, the bootloader trigger ("Track 1 + Track 4"), `solderless.engineering`, the `ericlewis/sp1-midi` Zephyr BSP, the `audiothingies` / `storagethingies` reference code, APPROTECT glitch attacks on the SP-1, eMMC extraction via test points or desolder, the 0/2/1/3 block interleaving for tape FF/RW, MIDI clock encoding in the audio data, the CS42L42 / TAS2505 / BQ24232 / CYBT-353027-02 / THGBMNG5D1LBAIL chips wired in the SP-1, or any technical question about the device's hardware, firmware, format, or reverse-engineering history. |
SP-1 Stem Player Reference Library
This skill provides curated reference material about the Teenage Engineering SP-1 stem player — an unreleased Kanye West / TE prototype based on the nRF52840 SoC. The community has reverse-engineered it over 3+ years (2024-04 to 2026-05+). This skill synthesizes that work into accurate, cited reference files so Claude can answer technical questions without making things up.
For state of dot-Justin's actual hardware — Unit A (Y4KNGJBE) and Unit B (Y4KNGJJ0) — read the sp-1-units skill instead. That's the live log of what's flashed on each device and what's safe to do next. This skill is for community / protocol knowledge.
The single most important rule for this skill: the SP-1 community has publicly called out AI hallucinations about this device. Before asserting any technical claim, read hallucination-watchlist.md and verify against the cited source.
Quick facts
- What it is: A 4-stem audio player. nRF52840 SoC. 4 GB Toshiba eMMC. Cirrus CS42L42 headphone codec + TI TAS2505 speaker amp. Cypress CYBT-353027-02 Bluetooth module. TI BQ24232 charger. 8 LEDs, 4 faders, 4 track buttons, transport rocker, function button, USB-C.
- What it does (stock): Plays 4 stereo stems at 24-bit / 48 kHz with effects (filter, distortion, gate, chorus/delay/echo) and tape FF/RW. Original units shipped with Donda or Jesus Is King album stems.
- Why it's hackable: The community bypassed APPROTECT in Jan 2025 (murray, voltage glitch). Track 1 + Track 4 + USB-C triggers a 60-second bootloader.
solderless.engineering makes flashing easy. Custom stems work on stock firmware if formatted correctly.
- Current state (synthesis date 2026-05-18): Lines forum thread closed (copyright/spam); community moved to Discord.
solderless.engineering is back online (since 2026-05-18) as a multi-app launcher with 4 apps: stem loader, firmware utility, device info, and spoom1. Multiple custom firmwares in development (emvee1968, virtualflannel_46386, TimK). Only public buildable BSP: ericlewis/sp1-midi (MIDI controller, not stem player). Custom-firmware web flashing is now publicly available via solderless's firmware utility.
Navigation — which file for which question
Always read first when working on this skill:
synthesis-log.md — what's covered through what date; freshness rulesupdate-log.md — every change since 2026-05-13, with what/why/source per intake batchhallucination-watchlist.md — the 3 explicit tkt1000 callouts + protocol-byte anti-patterns from 2026-05-13corrections.md — documented reversals (what was once believed wrong)known-unknowns.md — what's explicitly unresolved as of synthesis dateworking-confirmed.md — what is confirmed working with citationsgaps-index.md — broader triage of documentation / synthesis gaps beyond research unknowns (Tier 1 / 2 / 3 plus structural gaps)
Then for specific topics:
| Topic / question | File |
|---|
| Overview, history, who's who | references/01-overview-and-history.md |
| Chip-level architecture, peripheral map | references/02-hardware-overview.md |
| PCB layout, schematic, FPC, pin map | references/03-pcb-and-schematic.md |
| SWD, USB CDC, test points, ways to talk to the device | references/04-debug-interfaces.md |
| BQ24232 charger, battery, USB power routing | references/05-power-and-battery.md |
| CS42L42 + TAS2505 audio codec drivers, I²C config | references/06-audio-codecs.md |
| CYBT-353027-02 Bluetooth module | references/07-bluetooth-module.md |
| eMMC chip + protocol + sector layout + prefetch model | references/08-emmc-storage.md |
| Audio format on disk (the byte layout) | references/09-audio-format-spec.md |
| MIDI clock encoding in side-band data | references/10-midi-timing-encoding.md |
| The 0/2/1/3 block interleaving and tape FF/RW | references/11-block-interleaving-tape-fx.md |
| Audio engine internals (mixer, transport, varispeed) | references/12-audio-engine-internals.md |
| DSP effects (filter, distortion, gate, chorus/delay) | references/13-dsp-effects.md |
| APPROTECT bypass / glitch attack | references/14-approtect-glitch-attack.md |
| Bootloader CDC protocol | references/15-bootloader-protocol.md |
| USB album upload protocol | references/16-usb-upload-protocol.md |
| LED bit-bang firmware dump technique | references/17-led-bitbang-dump.md |
| Zephyr build environment | references/18-zephyr-build-environment.md |
ericlewis/sp1-midi BSP walkthrough | references/19-sp1-midi-bsp.md |
| Custom firmwares (public + unreleased) | references/20-custom-firmware-state.md |
| Stock-firmware custom stems workflow | references/21-original-firmware-stems.md |
| Ghidra disassembly findings | references/22-disassembly-ghidra.md |
| Physical disassembly / heat-and-pry | references/23-physical-disassembly.md |
| eMMC direct extraction (test points / desolder) | references/24-emmc-direct-extraction.md |
| 3D-printed accessories and mods | references/25-3d-printing-mods.md |
| Who's who, identity map | references/26-community-and-authority.md |
| Tools and utilities | references/27-tools-and-utilities.md |
Each topic has a paired FAQ file at the same path with -faq.md appended. For quick-lookup questions consult the FAQ first; for deep technical questions go to the main reference.
For primary sources (Lines posts, code, GitHub repos, manuals) see sources.md.
Top 15 quick-lookup answers
These are the questions that come up most often. For deeper detail follow the citation to the relevant file.
Q: How do I enter the bootloader?
A: Hold Track 1 + Track 4 and plug in USB-C. The device enumerates as USB CDC ACM for 60 seconds. The power button is NOT part of the combo (despite some old posts saying so). → references/15-bootloader-protocol.md.
Q: Can I play my own audio without custom firmware?
A: Yes. Stock TE firmware plays any correctly-formatted album. → references/21-original-firmware-stems.md.
Q: What's the eMMC clock speed?
A: 32 MHz in 1-bit mode. High Speed mode is not enabled. Don't try to go higher — unreliable. → references/08-emmc-storage.md.
Q: Is the audio 24-bit little-endian PCM?
A: No. That's a recurring hallucination. In-memory: right-aligned 24-bit in int32_t. On-disk: interleaved as L_mid, L_msb, R_msb, L_lsb, R_lsb, R_mid per stem. → references/09-audio-format-spec.md and hallucination-watchlist.md.
Q: What's the 0/2/1/3 block thing?
A: Physical disk order of the 4 TE blocks per sector. Enables tape FF/RW by reading less per sector at high speeds. → references/11-block-interleaving-tape-fx.md.
Q: Is solderless.engineering online?
A: Yes, back online as of 2026-05-18 after a complete rewrite. The site is now a multi-app launcher with 4 apps in sandboxed iframes (stem loader, firmware utility, device info, spoom1). Local mirror at assets/solderless-2026-05-18/ (canonical for new claims). The earlier 2026-05-12 community snapshot is preserved at assets/solderless-2026-05-12/ for citation stability. → references/27-tools-and-utilities.md.
Q: Who's TimK / tkt1000 / timknapen?
A: Same person. Lead firmware engineer. Owns github.com/timknapen/SP-1-dev. Not the same person as ericlewis. → synthesis-log.md identity map.
Q: What's in assets/audiothingies-2026-05-09.zip?
A: ericlewis's C++17 reference implementation of the stock audio engine. Shared in Discord 2026-05-09. Not in a public repo. → references/12-audio-engine-internals.md.
Q: How do I dump firmware on my own SP-1?
A: Three options: (1) LED bit-bang trick — flash a tiny custom firmware that exfiltrates via LEDs; (2) APPROTECT voltage glitch — murray's BeagleBone PRU setup; (3) SWD with mass-erase + reflash — read your own code only, not original firmware. → references/14-approtect-glitch-attack.md and references/17-led-bitbang-dump.md.
Q: Does the SP-1 have a factory SWD header?
A: No. You solder your own pads. → references/04-debug-interfaces.md.
Q: Can the bootloader read existing firmware?
A: No. Write-only. "you cannot" [ericlewis, Discord 2026-05-08]. → references/15-bootloader-protocol.md.
Q: What's the album upload speed?
A: Three data points: moecal1947's Python tool = ~0.75 KB/s (4.5 days per 311 MB album, USB control transfers); solderless web tool = ~10 KB/s (~9 hours per 311 MB album, CDC ACM fire-and-forget at 115200 baud — this is the public best; Tim Knapen's official help text states "1 minute of audio takes about 10 minutes to transfer" [code: assets/solderless-2026-05-18/stemloader/help/help.md]); ericlewis's theoretical max = ~4 MB/s (minutes per album, requires unbuilt USB bulk + CMD25 firmware). → references/16-usb-upload-protocol.md.
Q: Are there custom firmwares I can flash today?
A: Only ericlewis/sp1-midi (USB MIDI controller; does NOT play stems). emvee1968 and virtualflannel_46386 have unreleased ones with audio. TimK has private ones. → references/20-custom-firmware-state.md.
Q: My device looks bricked after disassembly — what now?
A: Reseat the FPC ribbon before assuming hardware failure. 90% of "bricked" cases are an FPC that looks plugged in but isn't fully seated. → references/23-physical-disassembly.md.
Q: How do I cleanly power down in custom firmware?
A: Mute codecs, reset audio chips, disable BT module, stop PWMs, disable eMMC supply (P0.14 low), disable button-common rail (P1.10 low), disable 3.072 MHz osc (P0.13 low), call sys_poweroff(). Function button longpress is the typical trigger. → references/05-power-and-battery.md.
Protocol Claude must follow
When working on SP-1 topics:
-
Read accuracy files first. hallucination-watchlist.md, corrections.md, known-unknowns.md, working-confirmed.md. These prevent specific past mistakes.
-
Cite every factual claim. Use [Lines #NNN, author, YYYY-MM-DD] or [Discord #channel, author, YYYY-MM-DD] or [code: path] or [GitHub: repo/file]. No unsourced claims.
-
Respect the synthesis date. Material is current through 2026-05-18. For "current state" questions (is solderless.engineering live? did emvee1968 release?), check synthesis-log.md + update-log.md and offer to verify with the user.
-
Don't conflate ericlewis with TimK. Two different people. Different repos. Different areas of expertise.
-
Don't conflate PO-32 with SP-1. libpo32 is for a different product.
-
Default to honest uncertainty. If a question isn't covered in this skill and isn't in the local corpus (see sources.md), say "I don't know — verify with the live Discord or ask TimK / ericlewis." Hallucinating a specific number, opcode, pin, or behavior is worse than admitting uncertainty.
-
The user (dotjustin) maintains this skill. Questions that come up during work get added to cc-skill/questions-for-timk.md (in the user's project directory, not in the skill) for later async resolution. Don't add to the skill itself without verifying claims.
-
The bundled material in assets/ is the redistributable corpus. Currently:
- TE manuals (PDF + DOCX)
solderless-2026-05-12/ — earlier community static snapshot of the public web tool (preserved for citation stability of older references)solderless-2026-05-18/ — current canonical mirror of the public web tool, multi-app launcher (stem loader, firmware utility, device info, spoom1)audiothingies-2026-05-09/ + storagethingies-2026-05-09/ — ericlewis's C++17 reference implementations (originally Discord attachments 2026-05-09)lines-thread-archive/ — agent-friendly subset of the 846-post forum mirror (full archive at github.com/dot-Justin/TE-SP-1-lines-thread-archive)SP-1-dev-2026-05-13/ — TimK's MIT-licensed repo (stemplayer_pins.h + 14 wiki pages)sp1-midi-2026-05-13/ — ericlewis's MIT-licensed public Zephyr BSP
Material not bundled and not redistributable: stock TE firmware binary, Kanye stems, anything from non-public Discord channels.
Synthesis date and freshness
This skill is a frozen snapshot synthesized through 2026-05-18. The Discord is active and things may have changed:
solderless.engineering may have shipped further app changes since 2026-05-18 (the 2026-05-18 mirror is at assets/solderless-2026-05-18/; live site may differ)- emvee1968's custom firmware may have been released
- virtualflannel_46386's custom OS may have been released
- ericlewis's "proper BSP" may have been released
- New corrections may have superseded current claims
For "what's happening now" questions, ask the user to summarize the current state from the live Discord rather than trusting this skill's snapshot.
Where to start (by intent)
- "I want to put my own music on my SP-1" →
references/21-original-firmware-stems.md
- "I want to write custom firmware" →
references/18-zephyr-build-environment.md then references/19-sp1-midi-bsp.md
- "I want to add Bluetooth" →
references/07-bluetooth-module.md (mostly known-unknowns)
- "I want to add an SWD header" →
references/04-debug-interfaces.md + references/23-physical-disassembly.md
- "I want to dump my SP-1's firmware" →
references/17-led-bitbang-dump.md (no glitch attack required)
- "I want to read the eMMC directly" →
references/24-emmc-direct-extraction.md
- "I want to understand the audio format" →
references/09-audio-format-spec.md + references/11-block-interleaving-tape-fx.md
- "I just want to know what the SP-1 is" →
references/01-overview-and-history.md
File inventory
sp-1/
├── SKILL.md ← this file
├── synthesis-log.md ← freshness metadata + identity map
├── update-log.md ← per-batch change history
├── hallucination-watchlist.md ← past AI errors to avoid
├── corrections.md ← documented reversals
├── known-unknowns.md ← what's still open
├── working-confirmed.md ← safe-claims list
├── gaps-index.md ← broader gap triage (T1/T2/T3 + structural)
├── sources.md ← where to find primary sources
├── references/
│ ├── 01-overview-and-history.md (+ -faq.md)
│ ├── 02-hardware-overview.md (+ -faq.md)
│ ├── 03-pcb-and-schematic.md (+ -faq.md)
│ ├── 04-debug-interfaces.md (+ -faq.md)
│ ├── 05-power-and-battery.md (+ -faq.md)
│ ├── 06-audio-codecs.md (+ -faq.md)
│ ├── 07-bluetooth-module.md (+ -faq.md)
│ ├── 08-emmc-storage.md (+ -faq.md)
│ ├── 09-audio-format-spec.md (+ -faq.md)
│ ├── 10-midi-timing-encoding.md (+ -faq.md)
│ ├── 11-block-interleaving-tape-fx.md (+ -faq.md)
│ ├── 12-audio-engine-internals.md (+ -faq.md)
│ ├── 13-dsp-effects.md (+ -faq.md)
│ ├── 14-approtect-glitch-attack.md (+ -faq.md)
│ ├── 15-bootloader-protocol.md (+ -faq.md)
│ ├── 16-usb-upload-protocol.md (+ -faq.md)
│ ├── 17-led-bitbang-dump.md (+ -faq.md)
│ ├── 18-zephyr-build-environment.md (+ -faq.md)
│ ├── 19-sp1-midi-bsp.md (+ -faq.md)
│ ├── 20-custom-firmware-state.md (+ -faq.md)
│ ├── 21-original-firmware-stems.md (+ -faq.md)
│ ├── 22-disassembly-ghidra.md (+ -faq.md)
│ ├── 23-physical-disassembly.md (+ -faq.md)
│ ├── 24-emmc-direct-extraction.md (+ -faq.md)
│ ├── 25-3d-printing-mods.md (+ -faq.md)
│ ├── 26-community-and-authority.md (+ -faq.md)
│ └── 27-tools-and-utilities.md (+ -faq.md)
└── assets/
├── TE-Stem-User-Guide.docx ← TE official, 16 KB
├── TE-Stem-User-Guide.pdf ← TE official, 59 KB
├── TE-Stem-Player-manual.pdf ← TE official, 509 KB
├── solderless-2026-05-12/ ← earlier static snapshot (preserved for citation stability)
├── solderless-2026-05-12.zip
├── solderless-2026-05-18/ ← current canonical mirror, multi-app launcher
├── solderless-2026-05-18.zip
├── SP-1-dev-2026-05-13/ ← TimK's docs repo + wiki snapshot
├── sp1-midi-2026-05-13/ ← ericlewis's Zephyr BSP snapshot
├── audiothingies-2026-05-09/ ← ericlewis's audio engine reference
├── audiothingies-2026-05-09.zip
├── storagethingies-2026-05-09/ ← ericlewis's eMMC + DiskManager reference
├── storagethingies-2026-05-09.zip
└── lines-thread-archive/ ← Lines forum mirror (agent subset)
8 top-level accuracy files + 27 deep references + 27 FAQ companions + bundled assets + this SKILL.md. Counts shift as bundles are added; see the assets/ listing for current inventory.
