Is there any sample example describing the "Enabling Secondary Media".
I want to boot x86 based board with primary OS booted from USB and want to deploy the image to SATA used as secondary media.
You say "deploy to SATA" but does that mean you need to reboot and only use the (different) kernel & rootfs from SATA or are you keeping with the running kernel and using the rootfs from SATA?
Are you testing an OS installer?
Is this using the x86 PXE support to boot into Grub?
Secondary media needs a lot of preparation in the device configuration to ensure that the correct device is identified without having problems with re-enumeration of /dev/sda /dev/sdb etc.
It's not possible to give a close example, we don't use x86 devices that often. The closest we have is on a Juno device:
The critical content is around line 88 - the device is identified as a label which can be available on multiple DUTs, each with a specific identifier in the device configuration: