This is meant as a follow-on presentation to my 'coreboot on ARM' overview from the 2016 conference (http://youtu.be/z-KpAA4_afs) with the goal to present 64-bit differences in the architecture itself and the way coreboot deals with them, with particular focus on the runtime resident component lifted from the Arm Trusted Firmware project. I'll give a basic developer overview of the Trusted Firmware codebase and what parts a new platform port needs to implement to be usable with coreboot. There may also be some war stories from our recent RK3399 implementation.