The latest boards work but the pass through port is flaky probably due to the length of the tracks from top to bottom of the board, 50% of completed boards work with an active device but not with a simple flash drive. The other 50% cause windows to give the same error even with an active device :(
PCB's being redesigned to move the pass through port closer to the connector to the motherboard which should resolve the issue :)

Another issue was too much solder paste bridging the SSOP28 chip requiring mopping up with de soldering braid, the next stencil will have the paste mask reduced from the default, the stencil is that recommended for SSOP28 at 12 mil thick.