There's been a lot of talk about the recent changes to SafetyNet and how it could impact devices in the future. The CTO of CopperheadOS says that the current implementation of SafetyNet is very haphazardly implemented, but will eventually evolve into real remote attestation.
Not convinced that the stock Android build on your Nexus smartphone or tablet does an adequate job of keeping your data secure? Copperhead Security has just released CopperheadOS for Nexus phones which delivers a self-protected kernel, better firewalling, concentrated app and service isolation...
Copperhead is an Information Security Firm based in Toronto and the company has been working on a custom ROM for Nexus devices that are said to be "hardened and secure".
Right now, you can download custom ROMs for the Nexus 5, Nexus 5X and WiFi Nexus 9.