> For the complete documentation index, see [llms.txt](https://docs.arkelectron.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkelectron.com/products/sensor/ark-flow/firmware.md).

# Firmware

ARK Flow runs the [PX4 DroneCAN Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html). As such, it supports firmware update over the CAN bus and [dynamic node allocation](https://docs.px4.io/main/en/dronecan/#node-id-allocation).

The flight controller flashes the node firmware over CAN.

{% embed url="<https://docs.px4.io/main/en/dronecan/#firmware-update>" %}

ARK Flow boards ship with recent firmware pre-installed, but if you want to build and flash the latest firmware yourself see [PX4 DroneCAN Firmware > Building the Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html#building-the-firmware).

* Firmware target: `ark_can-flow_default`
* Bootloader target: `ark_can-flow_canbootloader`

## Downloads

{% file src="/files/BjaVFVkettd00ULYzgIe" %}
ARK Flow Firmware
{% endfile %}

{% file src="/files/g5hpKwQTBBBo1PR1ia5l" %}
ARK Flow Bootloader
{% endfile %}

## Node Parameters

Set these on the ARK Flow, then reboot it. Use [QGroundControl](https://docs.px4.io/main/en/dronecan/#qgc-cannode-parameter-configuration), where each CAN node is a separate *Component X* under **Vehicle Settings > Parameters**, or the [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md). Defaults are those of the firmware above.

| Parameter          | Default | Description                                                                                                                                                                                |
| ------------------ | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `CANNODE_TERM`     | 0       | Set to `1` on the last node of the CAN bus                                                                                                                                                 |
| `CANNODE_PUB_IMU`  | 0       | Set to `1` to publish `RawIMU` messages on the CAN bus. PX4 also needs `UAVCAN_SUB_IMU` set to `1`                                                                                         |
| `SENS_AFBR_MODE`   | 0       | Distance sensor measurement mode. `0` short range, `1` long range, `2` high speed short range, `3` high speed long range                                                                   |
| `SENS_AFBR_S_RATE` | 50      | Distance sensor measurement rate in Hz below the switching distance                                                                                                                        |
| `SENS_AFBR_L_RATE` | 25      | Distance sensor measurement rate in Hz above the switching distance                                                                                                                        |
| `SENS_AFBR_THRESH` | 4       | Switching distance in m. The rate changes to `SENS_AFBR_L_RATE` above `SENS_AFBR_THRESH` + `SENS_AFBR_HYSTER` and back to `SENS_AFBR_S_RATE` below `SENS_AFBR_THRESH` − `SENS_AFBR_HYSTER` |
| `SENS_AFBR_HYSTER` | 1       | Hysteresis in m around `SENS_AFBR_THRESH`                                                                                                                                                  |

## Release Notes

### v1.16 - 3c45b562 - 2025-09-26

* Migrate to build server

### v1.16 - afb2c08b - 2025-08-06

* AFBRS50: Fix long range measurement publishing

### v1.16 - 2248a40e - 2025-07-10

* [AFBRS40: fix Range Mode switching](https://github.com/PX4/PX4-Autopilot/pull/25185)

### v1.16 - d0bfa548 - 2025-06-12

* [AFBRS50 fix scheduling and refactor](https://github.com/PX4/PX4-Autopilot/pull/24837)

### v1.15 - 82ff8744 - 2025-06-11

* Add DroneCAN RawIMU publisher

### v1.16 - 61036f77 - 2025-02-07

* Update to [AFBR 1.6.5 API](https://github.com/Broadcom/AFBR-S50-API/releases/tag/v1.6.5)
  * Improved distance sensor performance


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