> 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/flight-controller/ark-fpv/firmware/bootloader-flashing-using-dfu.md).

# Bootloader Flashing Using DFU

DFU can be used to flash or reflash the bootloader with the following steps.

1. With the board unpowered, hold the button next to the USB C port while connecting the USB cable to your PC.
2. Open <https://devanlai.github.io/webdfu/dfu-util/> in Chrome.
3. Select `Connect`, then select `DFU in FS Mode`.

   <figure><img src="https://1515919775-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FOwmEn1N45AR4WjMQhHlu%2Fuploads%2F91h9BJWzjVcO5ZOnpbIS%2Fimage.png?alt=media&amp;token=4ac739c0-8646-483b-a8ac-92067b207164" alt=""><figcaption><p>DFU Device Selection</p></figcaption></figure>
4. Now select the `@Internal Flash` option.

   <figure><img src="https://1515919775-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FOwmEn1N45AR4WjMQhHlu%2Fuploads%2FteDuDz2S65P7sJNDcyTp%2Fimage.png?alt=media&amp;token=90eac48f-9fb6-4ce6-b187-b0d2d0cef5af" alt=""><figcaption><p>Select the @Internal Flash Option</p></figcaption></figure>
5. Now choose the bootloader binary you wish to flash. In this case we are using the default ARK FPV PX4 bootloader which is compatible with PX4 and Ardupilot.

{% file src="/files/WKF1WXXNNsU0AZx6hyrK" %}
ARK FPV PX4 Bootloader Built on Commit [1043aebf5ddd8fd0f6825a27d9a060fa24b616eb](https://github.com/PX4/PX4-Autopilot/commit/1043aebf5ddd8fd0f6825a27d9a060fa24b616eb)
{% endfile %}

<figure><img src="https://1515919775-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FOwmEn1N45AR4WjMQhHlu%2Fuploads%2F61m2CCQnYou3nIlephRT%2Fimage.png?alt=media&amp;token=32f2a08a-8840-414a-93a1-c770ea53efd4" alt=""><figcaption><p>Firmware Selection</p></figcaption></figure>

6. Select `Download` to flash the firmware.

   <figure><img src="https://1515919775-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FOwmEn1N45AR4WjMQhHlu%2Fuploads%2F4wfOAlqLJPXtFXQhgn8P%2Fimage.png?alt=media&amp;token=2bafc4f0-92b4-4907-b183-18f03a1ce6ef" alt=""><figcaption><p>Start the Firmware Download</p></figcaption></figure>
7. The flash will finish and the firmware will start.


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