Kontron KTAM3874-pITX - Manual (Page 43)

KTD-S0051-D Page 39 Boot Order
KTAM3874/pITX User's Guide
16 Boot Order
For the purpose of keeping as many options as possible two different boot orders are available:
SPI x MMC x UART x EMAC (default)
MMC x SPI x UART x EMAC
Legend:
SPI Onboard SPI flash
MMC Only microSD TM card socket (not the e.MMC flash)
UART Only onboard UART0 (serial console, J1304)
EMAC Only Ethernet MAC 0 interface (J1600)
If you use the boot order 'MMC/SPI/UART/EMAC' you can bypass the Kontron bootloader in the SPI flash.
This circumstance gives more flexibility for own solutions.