Heads up for anyone using the expansion connectors on the BB X15. I spent much of yesterday debugging this issue. The BB X15 ships with a small piece of tape on each of the underneath expansion headers. I didn't realize this and connected the new BB X15 to my expansion board and the piece of tape got shoved inside the connector. Because of this some of my pins where not connected to the expansion board because they were blocked by the tape.
So when unpacking a new BB X15 make sure the remove those small pieces of tape from the connectors if you plan to use them. I bet the tape is left on the connectors because many people do not use the expansion and debris could get in the connectors.
Dan