Reverse‑engineered bike Bluetooth streams Google Maps to the dash

A developer captured raw Bluetooth traffic between a Suzuki motorcycle’s instrument cluster and its companion Android app, reverse‑engineered the 30‑byte frame format, and released an open‑source Android app that forwards Google Maps turn‑by‑turn notifications to the dash [Dev.to][Arjun Project].

The bike exposes a single vendor‑specific GATT service with two characteristics—one writable, one that sends notifications. Each packet is exactly 30 bytes: header, ASCII type byte, payload, checksum, and terminator. By decompiling the OEM APK with JADX, locating the checksum routine, and confirming it with Frida hooks, the developer mapped every field.

The resulting app, REDLINE, is written in Kotlin with Jetpack Compose. It intercepts Google Maps navigation intents, encodes each maneuver into the 30‑byte frame, and writes the packet over Bluetooth. The cluster then displays Google’s directions instead of the stock UI. REDLINE also reads telemetry packets, renders a live speed graph, records rides, and shows a clock when navigation is idle. The codebase totals about 14 k lines, includes 205 automated tests, and runs entirely on the phone—no cloud account or backend services.

Why it matters

• Proprietary vehicle Bluetooth protocols can be decoded with publicly available tools, opening the door for aftermarket integrations.
• Feeding Google Maps data into the cluster gives riders a familiar, regularly updated navigation source without relying on the manufacturer’s bundled provider.
• Exposing raw sensor data lets owners export ride statistics, build custom dashboards, or feed the data into third‑party analytics.

Editor’s take The work shows that a single developer can replace a manufacturer’s navigation stack, weakening OEM lock‑in and forcing regulators and insurers to reconsider reliance on proprietary data streams.