We have decided to remove the U13 Micrel switch for production going forward to solve the potential burnout issues we were seeing with nonconforming powered hubs. With this change, we will also not have a hard limit of load 500mA on the USB port. This change has already been put into production.
ECO:
-remove U13
-put zero ohm resistor across pin 8,7 of the U13 footprint
We have tested the change on a number of boards and it looks good. With any change, there is some risk involved so we want to let you know about the change.
Schematic (old) for Reference:
http://www.parallella.org/docs/parallella_schematic.pdf
Andreas