Updating firmware to use EV3 sensors

Hi everybody,
i’m trying to use lego ev3 sensors with brickpi but i don’t have the last firmware updated for the brickpi.
I checked and try this method : http://www.dexterindustries.com/BrickPi/about/design/brickpi-firmware-update/flash-new-brickpi-firmware-using-an-arduino/
with an arduino mega ADK but when i run ‘BrickPiFW_UC1 - Arduino Script.bat’ i have an error about an invalid device signature like the attachements.
Anyone have ever got this problem ?
Thank you