If you want to run code in EL1 before the Linux kernel then the ARM trusted firmware would be a good place to start
https://github.com/raspberrypi/arm-trusted-firmware
The Pi5 bootloader loads a default version build from the repo above but you can replace the file with your own version by specifying armstub=my_tfa.bin in config.txt
The custom ARM stub file can be loaded from the secure-boot verified boot.img file i.e part of the chain of trust
https://github.com/raspberrypi/arm-trusted-firmware
The Pi5 bootloader loads a default version build from the repo above but you can replace the file with your own version by specifying armstub=my_tfa.bin in config.txt
The custom ARM stub file can be loaded from the secure-boot verified boot.img file i.e part of the chain of trust
Statistics: Posted by timg236 — Thu Sep 05, 2024 9:18 pm