Default [SOLVED] Can't find debug USB on MK809III

Hi all

I've buyed a MK809III and I'm trying to root my device but I can't find the "debug usb" option on settings menu.

I've tryed to start my device in update mode but it only diplay a black screen and I don't understand what I've to do.....

Someone can help me on rooting the android stick?


[UPDATE] I've founded the solution in 4.2.2 developer options was hided... if you need you've to tap nine times over the "build number" information in the "about" menu.

Thx to all