Kind of answering myself here as having my chosen build on the card already allows EOSCard to make the card bootable and all good!
Well, nearly........
During the break I decided to splice my usb Canon mini cable with a female 3.5mm jack to allow for headphone monitoring.
The latest build here:
http://builds.magiclantern.fm/#/seems to have all audio menus disabled,
so I reverted to an earlier build where the options were available,
but.....
When I plug in the mini usb the screen goes blank, no matter what settings I change in the audio menu.
From trying to find an answer I see that One Percent has posted over on:
https://bitbucket.org/OtherOnePercent/tragic-lantern-6d/commits/allre: "7D audio seems mostly working."
and more recently:
"Solved 7D muting external audio. It was the wind filters.. now meters on all the time without filter_rec knock on wood"
I'm presuming these are builds in progress, but how can I try them?
I can't see any downloads related to the specific entries.
Sorry if I'm being a bit dim here.
Could someone please explain how I can try these?
Many thanks all!