Modified firmware and plugins

Firmware plugins are small programs that run inside the wheel itself. They can expose data that stock telemetry does not contain or change controller behaviour. Stock firmware cannot load them: the wheel first needs a special image containing the plugin host, after which LoEUC can install and remove individual plugins.

These are not phone plugins. A failed main-image write can leave the wheel without working firmware, while a fault in a control-related plugin can affect how the wheel behaves. Never use an image or package built for another model, never flash while riding, and never put a bench-only build on a real wheel.

Currently supported#

LoEUC only shows packages for the connected wheel family and validates their structure before a write. The app still cannot prove that a selected main image is safe for your particular wheel.

Modified images are not published as public downloads. Ask the author for the current production build. A flashable Lynx-S image ends in -prod.bin; files whose names start with DO-NOT-FLASH- are emulator-only and must never be installed on a real wheel.

Installing a plugin#

1. Install the matching modified firmware through “Firmware update” in the wheel menu. Before the first byte is sent, LoEUC displays the model, version, size, and checksum and asks again for confirmation.
2. Connect to the wheel and open “Wheel settings” → “Firmware plugins”.
3. Select a plugin from the bundled catalogue and tap “Install”. The wheel must be stationary.
4. Wait for the wheel to confirm the write. Do not close the app or interrupt the connection.

Removing a plugin frees its slot but does not restore stock firmware. Returning fully to stock is a separate flash of the original image.

Parking alarm#

The parking alarm is available for the Lynx-S and NOSFET Aeon. It can only be armed in the real parking mode, while the wheel panel shows P. Once armed, it remains active even if the wheel is taken out of parking mode.

A single brief jolt does not start the siren. The plugin first confirms continued movement, then warns with short beeps and headlight flashes. If the disturbance continues, it sounds a pulsed siren for 30 seconds and then returns to watch mode. If power is removed during an alarm, the siren resumes when the wheel is turned on again.

While armed:

• the wheel does not go to sleep on its auto-off timer;
• the normal long press cannot turn it off;
• a stationary wheel is prevented from entering balancing mode;
• panel buttons are reserved for PIN entry instead of their stock actions;
• a Lynx-S panel displays ARM P.

The PIN is a sequence of four presses on the three panel buttons. It is created on a dedicated LoEUC screen: press the buttons on the wheel, check the digits mirrored by the app, and then save. The correct sequence disarms without a phone; a wrong sequence immediately starts the siren. The power button neither disarms the alarm nor turns the wheel off, while watching or during the siren. Without a PIN, the alarm cannot be disarmed without a phone: the siren stops on its own after 30 seconds.

The alarm can also be toggled from LoEUC quick actions and a supported external display. The button follows the state echoed by the wheel rather than the tap, so a lost command is not shown as successfully armed.

The latest PIN-enabled alarm has been verified in the firmware emulator. Its sensitivity to wind, surface vibration, and real handling still needs validation on physical wheels.

Pedal feel: Lynx-S PID controller#

The “PID gains” plugin is only for the LeaperKim Lynx-S 009.0.04. It changes three balancing-loop gains without replacing the wheel's other settings:

• Ka · push-back — how strongly the pedal resists tilt;
• Kg · settling — how quickly a jolt is damped;
• Kc · pull — how load affects pull; a negative value produces stronger pull.

The old profiles and three opaque sliders have been replaced with a radar containing a separate axis for each gain. The screen always shows the stock value, selected value, and a plain-language description of the expected feel. Stock pedal hardness is on the same screen because the factory gain triplet is derived from it.

Moving a handle only edits a draft. The screen separately shows “Now on the wheel” and “Will become”; writing starts with one “Apply” button and is allowed only while the wheel is stopped. Experienced users can open “Exact values” and set Ka, Kg, and Kc separately. Returning to the centre/Stock disables the override completely and restores the firmware's own calculation.

The change is committed as a transaction: the complete new triplet is prepared separately and then activated together. Losing the connection halfway through should not mix old and new gains. The firmware host independently clamps values to the tested region both on input and on every balancing-loop tick; the app previews when a request has to be limited.

Those checks prevent values outside the researched region. They do not promise that every available combination will suit every rider or remain comfortable at every speed. The bench has verified the limits, stock fallback, and end-to-end application of the gains. Final pedal-feel evaluation must be done cautiously on a physical wheel, starting with a small change in a closed area.

Validation status#

• Main-firmware flashing from Android has been tested on a real Lynx-S and NOSFET Aeon.
• Plugin hosts and packages run through emulator scenarios using the real stock images.
• The latest PIN alarm and PID editor are not yet considered validated by physical-wheel use.
• Plugin installation from an iPhone is implemented but has not yet been tested on a real wheel.

If the wheel no longer boots after a flash, do not try random images. LoEUC Garage provides a separate “Try firmware recovery” action, but recovery is not guaranteed either and must only be used with an image for that exact model.