Also, by this time the memory controller in charge of DRAM has not been initialized yet, and so the SEC phase is also in charge of configuring the CPU caches to be used as temporary RAM (a technique known as CAR – Cache-as-RAM). Since very little can be done in Real Mode, one of the first jobs of the SEC phase is to switch the processor to Protected Mode. Rather, the first few instructions executed by the CPU are still legacy, 16-bit Real Mode instructions.
#UEFI EMULATOR MAC SERIES#
Hello and welcome back to the 2nd part of our blog post series summarizing our research in the fields of UEFI fuzzing and exploitation.