I'm following this tutorial on writing "bare metal" code for the Raspberry Pi 4. I've gotten the code working fine, but I'm left wondering how I could have figured any of this stuff out for my own. The basic process I'm following is to compile my code into a file called kernel8.img, put that on an SD card formatted in a certain way with a bunch of other files, and then plug that in and power on the Pi.

Where is the documentation that would tell me to do all this? I found this, which is a good start, but when it comes to how it loads data off the SD card it just says:

else if boot-mode == SD CARD

    Attempt to load firmware from the SD card

        Success - run the firmware

        Failure - continue

Clearly a lot is being left out - there's no mention of the need to name a file kernel8.img, no mention that the SD card needs to be formatted in fat32 (or at least the card I bought is), what flags need to be set on the partition, etc.

Where can I find actual detailed documentation on the boot sequence, and what protocols I need to follow to run my code on a Pi 4?

  • Check out this question and the 2nd more recent answer which has a link for updated boot information for the PI 4. Aug 16, 2023 at 18:54


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