[Q] LED light on stock topic

so... I've had my N6 for about month and a half and last week decided to root, weird thing was, I DID NOT KNOW that there was a LED light on it ... while using stock, the LED light did not come on at all and only when i installed CM12 that i seen the light.

I want to go back to stock but i want the LED light for notifications. has anybody encountered this problem? how do i fix it ?