Enable UART5 on beagle bone running debian

First mount debugfs:
mount -t debugfs none /sys/kernel/debug

Enable UART5:
echo 24 > /sys/kernel/debug/omap_mux/lcd_data9
echo 4 > /sys/kernel/debug/omap_mux/lcd_data8

Hardware Pins:
P8: 37 UART5_TXD
P8: 38 UART5_RXD

Device to access:
/dev/ttyO5

References:
http://www.jerome-bernard.com/blog/2012/06/04/beaglebone-serial-ports-and-xbees/