The i2C-6ULX-B carrier board provides a controllable GPIO LED (D17). The default Linux system to use as a heartbeat, you can also configure the user control.
LED lights (D17) default trigger mode is heartbeat, the following changes to none, before we can control.
# cd /sys/class/leds/cpu # echo none > trigger
Light on LED:
# echo 1 > value
Light off LED:
# echo 0 > value