If I remember right (search isn't finding exactly what I am looking for), the Mark I had no ability to run the aux input or the FM radio through the DSP (hence the lack of visuals in non MP3 modes). Based on the fact that the Aux screen normally displays DSP type stats and can't read the info it needs, I'm guessing it's not fully initializing the screen. Sounds like a potential bug to me.

Of course, this is going off memory of what I remember of the differences in the Mark 1 and 2. It may be horribly wrong