According to Digitimes, the reason for the sudden boom is the HTC Desire 10 series products, Google Pixel smartphones and the HTC Vive VR devices.

This is somewhat of a surprise as the sales of Google's previous smartphone models have been flat.  It is not clear if the Pixel smartphones will boost HTC's revenues substantially in the fourth quarter of 2016.

However HTC's smartphone shipments are expected to reach 6.5-7 million units in the second half of the year, with Pixel shipments accounting for just under half that,

HTC shipped 5.8-6.1 million smartphones in the first half of the year.