Weird, I suspect the problem is here"format=SANE_FRAME_GRAY last_frame=SANE_TRUE bytes_per_line=0 pixels_per_line=0 lines=0 depth=1
And simple-scan isn't handling the 0 results. This doesn't appear to be a valid result from SANE. Could you try debugging scanimage and see if they get the same results?
Looks like a driver bug to me, though simple-scan should handle invalid data gracefully.
