Microsoft's Zune HD, once a cause celeb for U.S. HD Radio proponents during its high profile introduction in 2009, may have reached the end of the line, says Bloomberg's Dina Bass. Further redesign and marketing of the Zune HD hardware platform will cease, the author claims, as Microsoft refocuses on pushing its Zune software written for popular mobile phone platforms.

Industry pundits note that despite some mildly favorable reviews early on, Zune HD never made much headway in challenging the market dominance of Apple's iPod, and thus may have devolved into a source of disappointment or even embarrassment at Microsoft.

A Microsoft spokesman recently questioned about the Zune HD's fate reportedly (and perhaps predictably) remained mum, though one official was quoted in an e-mail as saying that the current Zune HD would soon be available in Canada. Ironically, that country is the only nation in North America where HD Radio has yet to win significant government or industry support.