Hi, Re this diagram: http://udoo.org/download/files/pinout/Udoo_pinout_diagram.pdf I am trying to communicate with Xbee serial from linux with one of the PINS marked RX/TX 1, 2 3 coresponding to UART 4 and 5 (on gpio's 150-162, 160-161, 158-159), without any success. Though if I am using /dev/ttymxc3 I can see some but the bus hangs in no time. I would like to use /dev/ttymxc1|0. Does anyting has to be enabled in kernel before thes pins can be used as serial. If yes then which would be the devices associated. I see 3 devices /dev/ttymxc0 /dev/ttymxc1 and /dev/ttymxc3 Thank you.