For some reason mobile data in the Visitor Profile > Technology reports shows up as Unknown, even though it's almost all being collected. As a test, try segmenting your Technology reports by "Visits from a Mobile Device". 100% Unknown. Even for things like Browser/OS that are available in other reports. It seems like it'd be really smart to *at least* have data in the Technology reports broken out as Mobile instead of Unknown. But why not just put the accurate data in there?
Here's a list of Visitor Profile > Technology reports that could all use mobile data in them: