How can I make the TK1 SOM eMMC accessible over USB on the Ixora carrier board?

How should I connect the Ixora carrier board to beeing able to access the eMMC of the TK1 SOM assembled on it via USB mass storage mode (ums)?

(E.g. on the Apalis Eval Board one has to connect the hosts usb cable to X29 “RS232” during poweron, hitting any key in the serial console on the host, run ums 0 mmc 0, connect the hosts usb cable from X29 “RS232” to X50.)

JP2 should be removed, and USB cable connected to X9. After that ums should work exactly as on eval board.