Once power has been applied to the target, U-Boot bootloader will be fetched from the SPI NOR flash and executed. Boot messages will be printed out on the serial console. Redundant U-Boot environment is stored in the NOR flash as well, as depicted in the following image.

[[File:Xub-nor.png|thumb|center|350px|NOR flash default partitioning]] By default, U-Boot messages will be printed out on the serial console. environment is configured to retrieve    U-Boot automatically runs the autoboot macro, that loads the kernel and