Re: Hardware tested in Hull
The Pi's boot process is like this:
- VC4 turn on.
- VC4 boot rom finds the SD card and loads the VC4 boot image (bootcode.bin).
- The VC4 boot image loads the VC4 OS kernel (start.elf).
- The VC4 OS does all its initialisation and startup.
- The VC4 OS finds and loads the ARM kernel image (kernel.img).
- The VC4 OS turns on the ARM core.
- Your OS boots.
The ARM isn't involved in *any* of the boot process! By the time it gets power, the kernel image is already in memory! The VideoCore IV is doing all the work.
It'd be totally feasible for the Pi Foundation to extend the VideoCore OS (I think it's ThreadX?) to support network boot. But you'd still need an SD card to load it, and I suspect that it doesn't have USB or ethernet drivers, so it'd be a lot of work, and it's closed source anyway.