how to control LED on devkit8000

hi, everyone,
i am trying my devkit8000 the LED on / off on Android adb shell
i take the LED1, which is connected to GPIO186, so i do the following:

# echo 186 > /sys/class/gpio/export
# ls -l /sys/class/gpio/gpio186
lrwxrwxrwx root root 2000-01-01 02:08 gpio186 -

../../devices/virtual/gpio/gpio186

# ls -l /sys/devices/virtual/gpio/gpio186
-rw-r--r-- root root 4096 2000-01-01 02:09 uevent
lrwxrwxrwx root root 2000-01-01 02:09 subsystem -

../../../../class/gpio

drwxr-xr-x root root 2000-01-01 02:09 power
-rw-r--r-- root root 4096 2000-01-01 02:09 direction
-rw-r--r-- root root 4096 2000-01-01 02:09 value
-rw-r--r-- root root 4096 2000-01-01 02:09 edge
# echo 0 > /sys/class/gpio/gpio186/value
# cat /sys/class/gpio/gpio186/value
0
# echo 1 > /sys/class/gpio/gpio186/value
# cat /sys/class/gpio/gpio186/value
0