On FiiO X3 locking-up:
There may be similarities in the curcumstances of our X3 lock-ups. In my experience, this has only ever happened when I am browsing my music files and listening at the same time. In each case, I reset it quickly and continued without problems. So far, it has happened four times since I bought the device in mid-October.
It has not happened while just listening to music. It has not happened whilst using the X3 as a DAC/AMP connected to my laptop and desktop speakers.
Perhaps we could all try to describe the circumstances of our X3 lock-ups in detail, so that FiiO can resolve it more quickly for us all.
It is quite annoying and frustrating, as it ruins our enjoyment of our music. So I am hoping this can be resolved in a FW update very soon.