I am not sure if I have one of the early Japanese models, I can check the firmware code. But mine sounds much better once I went back to the original software. No noise, no funny static, no issues with either headphone output, and no changing volumes in one ear all of a sudden. I will not be downloading any updates until I am sure they are perfect.
I am quite happy with the X1 overall, my only complaint is the noise issue, but it sounds like a software issue. Combined with the Creative E5 and Aurisonics ASG 2.5 IEM, it is a bass monster that has great sound through the entire spectrum. Very good unamped as well with the ASG 2.5. I am a drummer and prefer a lot of bass, so I add the E5.