Comment 1 for bug 855921

Okay, so this one might be a little tricky...

Our preseed is coming in over http (via the url=http://... parameter in the kernel command line). That necessitates a network up.

I think what we'll need to do is to force the orchestra configuration to default the choose_interface to eth0, and document that this needs to be tweaked for any systems where that's not the case.