Security researchers presenting at CCC break down Triangulation, and it’s full of juicy tidbits: https://securelist.com/operation-triangulation-the-last-hardware-mystery/111669/
Operation Triangulation: The last (hardware) mystery
Recent iPhone models have additional hardware-based security protection for sensitive regions of the kernel memory. We discovered that to bypass this hardware-based security protection, the attackers used another hardware feature of Apple-designed SoCs.