What ScreenTune Code Is Open Source
ScreenTune splits its code along one line: what runs on the vehicle, and what runs on a desktop computer. The vehicle side is where trust matters, so most of it is open source and readable before you install it.
What runs where, and what you can read
Section titled “What runs where, and what you can read”| Component | Runs on | Source |
|---|---|---|
| Tweak install/restore scripts | CMU (vehicle) | Open (Shell) |
| mfy-hotkeys | CMU (vehicle) | Open (C, MIT) |
| MFY Gauges | CMU (vehicle) | Open (web JS/HTML) |
| mfy-fastdata | CMU (vehicle) | Closed (C) |
| mfy-gpsdata | CMU (vehicle) | Closed (C) |
| ScreenTune desktop app | macOS/Windows/Linux | Closed (Rust, Tauri) |
| ScreenTune CLI | macOS/Windows/Linux | Closed (Rust) |
Why the vehicle-side code is open
Section titled “Why the vehicle-side code is open”The CMU is the small Linux computer behind your car’s infotainment screen. Anything installed on it should be readable before you put it there, so you can see exactly what it changes.
So the parts that change your system are open:
- Install and restore scripts are shell. They are the code that actually modifies the CMU. You can read every line of what they touch and what they put back.
- mfy-hotkeys is C under an MIT license, published with each release.
- MFY Gauges is web code (JavaScript and HTML) running in the CMU’s browser layer.
Anyone can read these and check exactly what they do before installing.
The two closed vehicle modules
Section titled “The two closed vehicle modules”mfy-fastdata and mfy-gpsdata are written in C and not published. Both are read-only telemetry: they read vehicle data and hand it to the gauge display. Neither writes to the car’s data bus or changes how the car behaves. This is documented further in attack surface.
Why the desktop app is closed
Section titled “Why the desktop app is closed”The ScreenTune desktop app (Tauri/Rust) and CLI never run on the vehicle and have no access to vehicle systems. Their job is to:
- Collect your vehicle’s configuration details
- Select and assemble the correct files for that configuration
- Write the USB drive
The files they assemble are the open vehicle-side scripts above. The app is the packaging step, not the thing that runs in your car.
Source repositories
Section titled “Source repositories”| Component | Availability |
|---|---|
| mfy-hotkeys | Published with each release (MIT) |
| MFY Gauges | Published with each release |
| Install/restore scripts | Included in the USB payload and published |
For what runs on the CMU and what it can reach, see attack surface and the safety FAQ.