I have downloaded the gerber files for the sabre board to determine the connector positions on the board.
There is a small inconsistency on J20.
when holding the board with the power-connector pointing north and ethernet connectors south:
Gerber Files: Pin 1 on J20 is top-right
Board: Pin 1 on J20 is bottom-right
Based on the schematic, Pin 2 of J20 is connected to GND. Resistive measurements show this is the top-right pin on the board and (just like the rest of the schematic for J20) is consistent with the board layout on the sabre hardware. Not with the gerber files.