Thank you, this really helps me!@Rafcy : Just the try to install one tweak most probably does not brick your system. And you do not have to install it at all. If the screen pops up, if you want to install the tweak, you can hit cancel. The pop up of the install screen already would be the proof, that the system is rooted/that serial access was done/that you can install tweaks via usb.
If it was not done, no install popup will be shown at the mzd screen.