NVM found how to do it.
If you stop the gl_fan service completely, you can control the fan manually:
/etc/init.d/gl_fan stop
echo 255 > /sys/class/thermal/cooling_device0/cur_state
The value is from 0 to 255. Even changing the temperature in gl_fan, if you don’t stop the service, the service will change the fan speed down 0.
So until the gl_fan service is improved, i would just say put it at max. It’s not very loud from 2m away where i’m sitting.
My router is sitting happy at 56 deg now compared to nearly 80 it was before.