My Sirius Sportster did a channel update this morning, any idea what the change was? Also, an oddity I noticed. I have an XM antenna in my car, and the unit, after powering up with full signal, after 4 seconds, goes to channel update, and then reports "antenna not detected". I gave up after 3-4 tries. When I got to work and plugged in to my boombox (with Sirius Antenna), it worked fine (after updating the channels). Odd?