> 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/gps/ark-sam-gps/ardupilot-instructions.md).

# ArduPilot Instructions

## Firmware Setup

The IIS2MDC magnetometer driver was added in January 2025 and requires ArduPilot version 4.6 or newer.

Use the [ArduPilot Custom Firmware Builder](https://custom.ardupilot.org/) to compile firmware for your autopilot with the IIS2MDC driver. Select `IIS2MDC Compasses` under `Compass` for your board.

<figure><img src="https://1515919775-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FOwmEn1N45AR4WjMQhHlu%2Fuploads%2FiCZtI2q9oJxdZxbBuWx6%2Fimage.png?alt=media&amp;token=7444ce77-d6b7-4f89-ae89-7d4ff64aafd0" alt=""><figcaption></figcaption></figure>

This PR can be backported into previous releases of ArduPilot.

<https://github.com/ArduPilot/ardupilot/pull/28602>

Configure [SERIALX ](https://ardupilot.org/copter/docs/parameters.html#serial-parameters)to GPS on the port the GPS is connected to. On the ARK FPV GPS port, this is set by default and is plug and play.

Ensure [COMPASS\_EXTERNAL ](https://ardupilot.org/copter/docs/parameters.html#compass-external-compass-is-attached-via-an-external-cable)is set to 1 to auto detect the magnetometer on I2C.


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