They have a lot of power, and plugging something like a thunderbolt device in can load an option ROM that runs there [1]. It is one of the reasons linuxboot is

They have a lot of power, and plugging something like a thunderbolt device in can load an option ROM that runs there [1]. It is one of the reasons linuxboot is such an important project [2]. There is a great talk on why linuxboot is required [3]. [1] https://trmm.net/Thunderstrike https://trmm.net/Thunderstrike [2] https://www.linuxboot.org https://www.linuxboot.org [3] https://trmm.net/LinuxBoot_34c3 https://trmm.net/LinuxBoot_34c3