Hi guys, 5D mkIII owner having a thick moment - help appreciated. Downgrading with Mac OS Sierra Macbook Pro to Canon 1.3.4 to 1.2.3 so I can run ML. I've downloaded the ML software from the website (http://builds.magiclantern.fm/), but I haven't found a way/firmware to downgrade my 5D mkIII yet to 1.2.3 - and ML says it cant' do anything until it sees 1.2.3, can anyone advise please? Thanks - Tim