I just managed to get my 3B to tftp boot, and as far as I can see the boot process always looks for, in order:
bootcode.bin
config.txt
start.elf
fixup.dat
config.txt
config.txt
cmdline.txt
bcm2710-rpi-3-b.dtb
config.txt
kernel7.img
I have a few questions regarding this:
1) Is there a way to specify which kernel to boot, other than kernel7.img? Is there a way to do this other than by symlinking the file?
2) What types of kernel images are supported for kernel7.img? All of my other aarch64 machines use UEFI and the vmlinuz images I use on that show up as, for example:
vmlinuz-4.9.196-1.el7.aarch64: MS-DOS executable, MZ for MS-DOS
The Raspbian images show up as:
kernel7.img: Linux kernel ARM boot executable zImage (little-endian)
Is there a way to use the former kernel directly on Raspberry Pi 3 / 4?
If not, is there a way to tftpboot Tianocore UEFI and have that tftp load the kernel? The goal is to be able to load the exact same kernel from both my UEFI aarch64 machines and the Pi 3 and Pi 4 machines.