Honda ADV350 route USB cable with Quad Lock phone mount handlebar installation 

After filming the vid I have actually dremelled a 5mm gap in the lip, and the cable sits in it nicely. I pondered on drilling a hole through the side of the box and then fitting a rubber grommet to reseal it, but tbh there's a few issues with that. Access isn't good for the drill , plus you'd have to make a big enough hole to pass the cable head through, plus the exposed cable head would be liable to corrode when not attached to the phone (although I suppose you could find a little plastic cap to protect it). Good luck!