Hi, since I'm currently change my rockpro64 setup I came across this. With the kernel from ayufan you need to set PWM_CTL to /sys/devices/platform/pwm-fan/hwmon/hwmon3/pwm1 for my self compiled one I need /sys/devices/platform/pwm-fan/hwmon/hwmon0/pwm1 But I got it only working with one entry for PWM_CTL e.g. PWM_CTL = "/sys/devices/platform/pwm-fan/hwmon/hwmon0/pwm1", after that you need to start ats again sudo systemctl stop ats sudo systemctl start ats initially the fan should start immediately for a short period of time. In case it is even a different one on your kernel you can find the right one using this command. sudo find /sys -name pwm1 | grep hwmon So far I'm not sure which kernel parameter or modul changes this. Martin