how to brick note 4?

Hi, I need to complete brick my note 4 n910f. Already install 4 files kk and lollipop firmware and don't help me. I've random reboots and now always reboots.

I need to complete brick (can't enter in download mode) because I've knox 1 and in the sat they say I don't have warranty because knox to 1.

I tried to put note 3 and n910c firmware and note refuse it.

Any help?

Cheers.