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