A Python tool to safely read the Keihin ECU on a 2010 Bonneville T100 over K-Line (KKL cable) or a Bluetooth ELM327, plus the reverse-engineering research behind it. Phase 1 (read-only comms) of an open tuning toolchain to replace the closed TuneECU app. Read-only by construction: safety.assert_read_only() runs on every outbound request before it hits the wire and refuses all write/flash services (0x27, 0x31, 0x34/0x36, 0x35, 0x37, 0x14, 0x11, 0x2E) and programming sessions, so a bug cannot brick the ECU. Verified frames match TuneECU byte-for-byte in tests/verify_protocol.py. Protocol constants recovered from the TuneECU APK (not guessed): ECU address 0xD5, K-Line tester 0xF5, format byte 0x80|len, additive mod-256 checksum. Includes the full TuneECU map catalogue (1811 entries) extracted to maps.json, searchable and filterable by ECU type and mechanical-vs-LCD odometer. research/ documents the Security Access seed/key algorithm, recovered as standard AES-128 (three embedded keys), with a self-testing reference impl verified against FIPS-197. This is write-path material, kept outside the read-only package. STATUS.md and README.md capture full context, the risk register, and where we left off: comms built but not yet run against the bike; next step is wiring the VAG KKL cable to the Triumph connector and running the first scan.
11 KiB
Triumph Bonneville tuning project — status & context
Bike: 2010 Triumph Bonneville T100, 865cc air-cooled parallel twin, Keihin ECU (Renesas SH7054), mechanical/analog odometer.
Goal: an open-source Python toolchain to read and (eventually) tune the ECU, replacing the closed TuneECU app. Ultimate hardware path: SAI removal, O2 delete, airbox removal, full exhaust — each needs a matching recalibration.
Last updated: 2026-08-10. Not getting to actual tuning this week — this doc is the cold-start reference to pick it back up.
TL;DR — where we are
- Phase 1 (read-only comms) is built, not yet run against the bike. Nothing has touched the ECU. No hardware connected yet.
- Next real step: wire the cable to the Triumph connector correctly, then run
tunie infoto read the ECU's identity, current map ID, and fault codes. - Blocker: the wired cable is a VAG KKL — right cable type, wrong plug for this bike. Needs an adapter/re-pin to the Triumph diagnostic connector. This is the one genuine (electrical) risk and must be confirmed against a wiring diagram before plugging in.
- Big win: the ECU's security-access seed/key algorithm was fully recovered from the TuneECU APK — it's AES-128 with three embedded keys. Documented, reference-implemented, and verified. This is write-path work, quarantined outside the read-only tool.
Directory map
/Users/dylan/dojo/tuner/
tunie/ the read-only Python tool (installed, working)
src/tunie/ package source
tests/ protocol verification (passes)
maps.json 1811 extracted TuneECU maps
README.md tool-level docs
research/ WRITE-PATH reverse engineering (kept OUT of the tool)
keihin_seedkey.py AES-128 seed/key reference impl (self-testing)
FINDINGS.md seed/key writeup
work/ decompiled TuneECU
jadx_out/ Java decompile (read-only, best for reading logic)
apktool_out/ smali decompile (rebuildable)
TuneECU.apk original
TuneECU-logging.apk a clean rebuild (no real instrumentation yet)
samplez/ pristine original TuneECU.apk (git repo)
STATUS.md this file
RESEARCH.md the original (LLM-written, partly wrong) research brief
What has been built
tunie — read-only KWP2000 diagnostic tool
Installed and working. Commands:
tunie ports # list serial devices
tunie info --port /dev/cu.usbserial-XXXX # interrogate ECU (KKL cable)
tunie info --port /dev/cu.OBDII --adapter elm327
tunie dtc --port ... # fault codes only
tunie maps Bonneville --ecu 0 --odometer mechanical
tunie extract-maps <arrays.xml> # rebuild maps.json
tunie -v info --port ... # verbose: log every frame
Supports both a wired K-Line KKL cable (--adapter kline) and a Bluetooth
ELM327 (--adapter elm327) behind one interface.
Read-only by construction. src/tunie/safety.py::assert_read_only() runs on
every outbound request inside Transport.request(), before any byte reaches the
serial port. It allows only an allowlist of query services and refuses all
write/flash services (0x27 SecurityAccess, 0x31 erase, 0x34/0x36 write,
0x35 upload, 0x37, 0x14, 0x11, 0x2E) and all programming diagnostic
sessions. A bug cannot brick the ECU because the write path is not implemented.
Module layout:
safety.py read-only allowlist, enforced before transmit
kwp2000.py ISO 14230-3 framing, checksums, negative-response decoding
triumph.py Triumph constants recovered from the APK
identify.py the read-only interrogation sweep
maps.py TuneECU map catalogue extraction + search
cli.py command-line entry point
transport/
base.py Transport ABC; routes every request through safety
kline.py FTDI/KKL cable, raw serial, break-condition fast init
elm327.py ELM327 adapter, using TuneECU's own AT init sequence
tests/verify_protocol.py passes: it asserts our frames are byte-identical to
TuneECU's and that every write service / programming session is blocked.
What was learned (all recovered from the APK, not guessed)
Protocol facts (source: com/tuneecu/m.java + MainActivity.java)
| Parameter | Value | Notes |
|---|---|---|
| ECU address | 0xD5 |
from Ld() framing + ATSH81D5F5 |
| Tester address (K-Line) | 0xF5 |
not 0xF1 — that's another brand |
| Format byte | 0x80 | length |
long form (0x80 + length byte) when >120 B |
| Checksum | additive sum mod 256 | Ub() in m.java |
| Init | fast (ATTP5) or 5-baud (ATTP4+ATIIAD5) |
address 0xD5 |
| ECU type code | 0=Keihin, 1=Sagem, P=Bosch |
ecu string-array |
Reference frames (verified in tests):
81 d5 f5 81 cc StartCommunication
82 d5 f5 1a 80 e6 ReadEcuIdentification 0x80
84 d5 f5 18 00 ff 00 65 ReadDtcByStatus
RESEARCH.md guessed target
0x10/ source0xF1and a 16-pin OBD-II port. Both wrong for this bike.
Map database
Extracted TuneECU's full catalogue: 1811 entries in tunie/maps.json.
TuneECU's own database distinguishes "Mechanical odometer" from "LCD
odometer" Bonnevilles — they are not interchangeable, and this is the ECU
generation split. For a 2010 mechanical-odo 865:
- Stock baselines (
:0:Keihin, mechanical odo):20187production silencers,20188aftermarket silencers20191/20192same, up to VIN 739050, E25 fuel
- Exhaust maps:
20262–20265,20313–20316(Arrow 2-in-1 / 2-in-2)
RESEARCH.md recommended
20498as an "OEM Arrow, safe rich baseline." It is actually a Thruxton, LCD-odometer map — wrong model AND wrong ECU generation. Do not use it.
Security Access seed/key — RECOVERED, it's AES-128
Source: com/tuneecu/m.java method Vb(). Full writeup in
research/FINDINGS.md; working reference in research/keihin_seedkey.py
(python3 research/keihin_seedkey.py → all self-tests pass).
- The algorithm is standard AES-128 (verified: all 256 T-table entries match AES Te0; reference passes the FIPS-197 known-answer vector). It is not the Honda XOR/bit-shift scheme RESEARCH.md predicted.
Vb()AES-encrypts a 128-bit seed block with one of three embedded keys (iArr4, m.java:5351), selected byMainActivity.h7 ∈ {0,1,2}, and returns the first ciphertext word as the 4-byte key (Gd()sends27 02 <key>).- The three keys (little-endian):
h7=0: ef704ca051b800cc9287df6a3511a978 h7=1: d4b15ff4c92ab7f098316e7a5b11ac39 h7=2: dc9fdba46f2fad18a4b8e1123c7183c2 - Still open (framing, not crypto): which h7 applies to the mechanical-odo
865, and the exact seed-block padding (
Ie[1..3]from the response + fixed0x03/0x01;Ie[0]set on an earlier path). One captured (seed, key) pair resolves both.
The logging APK
work/TuneECU-logging.apk is a clean apktool rebuild of the original (~17 KB
delta = re-signing/recompression). No custom instrumentation; all Log calls are
TuneECU's own, gated behind its debug boolean; no debuggable flag. It does not
currently capture seed/key at runtime — but it's the right vehicle for the
validation step (see next steps).
The cable (VAG KKL) — what to do
A "VAG KKL" 409.1 cable is the correct cable class (K-Line), but wired for the VW/Audi OBD-II socket, which this bike does not have.
Step 1 — identify the chip. Plug into the Mac, run tunie ports:
/dev/cu.usbserial-XXXX→ FTDI, ideal, no driver./dev/cu.wchusbserialXXXX→ CH340; works but install the CH340 macOS driver.- nothing → driver missing.
Step 2 — adapt the connector (the risk step). The VAG plug puts K-Line on OBD-II pin 7, +12V on 16, ground on 4/5. The 2010 Bonneville uses Triumph's proprietary diagnostic connector (under seat/side panel), not OBD-II. You must adapt/re-pin K-Line + switched-12V + ground to the correct three Triumph pins.
Do not plug in until the Triumph connector pinout is confirmed against a wiring diagram or the known TuneECU-cable wiring. Wrong pin damages the transceiver. This is the one risk software can't remove.
Next steps (in order)
- Identify the cable chip —
tunie ports, install CH340 driver if needed. - Confirm the Triumph diagnostic connector pinout — service manual / wiring diagram. Build the adapter (K-Line, switched +12V, ground).
- First scan (safe): ignition on / engine off,
tunie info --port …. Yields ECU ID, currently-flashed map ID, DTCs. If fast init times out, try--init slow. This resolves which stock map is actually on the bike. - (Later, Phase 2) ROM dump for a recovery image — requires deliberately
enabling
0x35upload; blocked in the read-only tool by design. - (Later, Phase 3) Checksum patching — not yet investigated; needed before any modified map can boot.
- (Later, Phase 4) Write path — validate the AES seed/key against a captured pair first; ideally against a spare ECU, not the bike's only one.
Optional now: capture a real seed/key pair
Write a minimal smali patch to work/apktool_out that logs every KWP frame
(patch the BT send/receive in d.smali) to logcat, rebuild, run one real TuneECU
Security Access against the bike, and capture the 27 01 seed + 27 02 key.
Then check compute_key(seed, h7) reproduces it — validates the whole AES port
and pins down h7 + padding.
Risk register
| Area | Status |
|---|---|
| Software bricking | Eliminated — write services structurally unreachable in tunie. |
| Electrical / wiring | LIVE — VAG cable ≠ Triumph connector; confirm pinout before plugging in. |
| Seed/key correctness | Algorithm recovered + AES-verified; which-key + padding need one captured pair. Phase 4 only. |
| Firmware checksum | Not yet investigated. Needed before flashing a modified map. Phase 3. |
| Single ECU, no spare | Read-only-first mandatory; validate any write path against TuneECU before trusting ours. |
Tuning theory (from RESEARCH.md §9 — this part is sound)
- SAI removal: flip the software SAI flag or the ECU throws a DTC; SAI air also corrupts AFR readings on a dyno, so disable it before any fuel tuning.
- O2 delete / open loop: removing narrowband O2 + disabling closed-loop lets you command a richer light-load AFR (~13.5–13.8:1 vs 14.7) — cools the air-cooled top end and fixes the snatchy off-idle response.
- Airbox removal & full exhaust: both raise cylinder fill (VE / scavenging);
fuel tables must be enriched or it runs lean under load. Community airbox maps
derived from
20188provide pre-calculated enrichment.
XDF definition files (to edit the .bin in TunerPro) are sold by OldSkullTuning and Tuniverse (~€70) for the SH7054 — a later purchase, only once we're editing.