I was able to load firmware on the arduino with XLoader. Seems to be working at this point. The update script detects the version properly, tries to download the latest version but fails, presumably because it is downloading the latest (non-arduino compatible) version.
I'm new to this scene, trying to get up and running with a RPi2 and UNO, this is what I'm getting when trying to update w/ legacy:
pi@raspberrypi ~/brewpi-tools $ sudo python updater.py --ask
Using interactive (advanced) update with user input...