Magic Smoke and PTC's
@stevenbell teaches a course in Introductory Digital Engineering at Tufts University and has bought many UPduino’s. He suggested that the ferrite bead be replaced with a PTC as he was seeing students shorting out their boards leading to burning out the ferrite bead.
If true, this is a pretty worrisome failure as the board is used by makers as well as students for introductory engineering courses, many of whom are novices and would likely end up with a similar failure.
Read more about at the tinyVision blog.