I have one I/O expansion shield V7.1 from DFRobot.
(link)
some vendors say that it is compatible with the YUN. On mine, its different : a 5V pin (of the SDA/SDL connector of the shield) has physical contact with the ethernet port (and maybe a GND pin too) .
Look at the photo I have attached
Does anybody have experience with this shield ?
Solution after 3 hours : Use stacking headers