AM4378: Bootloader - clarification about NOR boot

Part Number:AM4378

Team,

-It does not seem that any of our development cards make use of the GPMC NOR boot. Correct?

-Are there any restriction to use the NOR boot on GP device and secure device (standard secure boot)?
Is NOR boot fully supported by the tools for secure tools?

-The U-boot guide does mention GPMC  NOR boot but the description does not seem very clear
http://software-dl.ti.com/processor-sdk-linux/esd/docs/05_00_00_15/linux/Foundational_Components_U-Boot.html#norAre there any Sitara board supporting GPMC NOR boot?Is there a complete procedure/example available?

Thanks in advance,

Anthony