@Boss_Kwei, It's only a problem for newbies like me that don't know it doesn't work. The first time I tried flying my quad, the default min PWM was high enough for the quad to lift off. I was in my backyard (with lots of trees) only intending to lift off and check hover stability. You can imagine my surprise when as soon as I armed it, it lifted off and flew up into one of the trees. It busted off the GPS and every prop before falling to the ground still buzzing furiously. Now I know that ESC Cal routine is not some clever new algorithm that figures out min and max output in a blink of an eye...so, yeah, I guess it's not a problem. (And I now have the kill switch mapped).