We’ve been waiting for this book for a while!
https://firmwaresecurity.com/2016/08/02/rootkits-and-bootkits-new-chapter-available/
https://firmwaresecurity.com/2017/02/15/rootkits-and-bootkits-boot-update/
https://firmwaresecurity.com/2015/08/06/no-starch-press-rootkits-and-bootkits/