Just for information I have managed to install Hass.io to my Raspberry PI using just my ChromeOS laptop and the Chrome OS recovery Utility
You will also need a Android compatible ChromeOS device to allow you to install Zarchiver to convert the Bz2 image to a zip file. A Zip file is required by the recovery utility to image the SD card.
Installation
Download the Hass.io image
Install zarchiver from the Google play store
Install the Chrome OS Recovery Utility from the Chrome webstore
Use zarchiver to extract the hass.io . bz image to a .img
Use zarchiver to compress the .img to .zip
Run the Chrome OS recovery utility
Select the Cog icon in the top right of the windows
Select use local media
Select the .zip image created earlier
Select the SD card to image
This will create the SD image. It would be nice if the Hass.io image could be supplied as a .zip download to save the above steps, as this would then be compatible with all ChromeOS hardware