Could someone explain the boot partition to me?

[Mentaluproar]

Using ayufan's buster minimal image, I noticed uboot seems to ignore the boot partition and instead looks at the boot folder in the root partition.  So if I update extlinux to load additional modules and look at sata for the root partition, it will ignore the changes because the system writes them to the boot partition instead of where uboot actually looks for it.

I have my root moved to an hard drive on sata side and want to use the SD card only for boot, but I seem to be missunderstanding something about how the boot process works.

Yup, when you are running rootfs somewhere other than the SDcard, and using the SDcard to boot, all updates are made to /boot/. You need to duplicate them to the SDcard, I have a little script syncsd to do it for me

Code:

sudo mount /dev/mmcblk0p7 /mnt/
sudo rsync -ax --delete /boot/ /mnt/boot/
cat /mnt/boot/extlinux/extlinux.conf

There's a way to configure the fstab to point to the SD card so updates and extlinux initramfs changes are put in the right place without a sync command.  I just can't find an example of how and my own attempts just break things.