mobile

Hello.

I am used to Nexus and Moto devices and this is my first Samsung, and have a few questions.

1) I keep hearing that T-Mobile is not a locked Boot-loader. Does that mean I do not need to worry about "tripping" the KNOX?
2) If I enable the Soft button Navbar is there a way to also disable the lights for the capacitive ones?
3) Is there any mods that enable double tap to wake?

Thanks, I'm sure some of these are dumb to long time Samsung guys.