Hi,
Usually ONIE (or a bootloader) will populate the /host/machine.conf with platform specific information.
From there a few places will use this information, most notably /etc/rc.local
I've always found the `platform` and `hwsku` kinda confusing,
- `platform` means your hardware platform which initially comes from /host/machine.conf
configurations under /usr/share/sonic/device/$platform
- `hwsku` refers to a default port configuration for your platform which initially comes from minigraph.xml or default_sku
configurations under /usr/share/sonic/device/$platform/$hwsku
Thanks,