title: how does an ARM boot from a sd card?
body: <p>I'm a bit lost regarding the boot concept of a modern system from a serial flash device. Having programmed quite a number of simple micros ranging from 8 bit PICs to 32 bit Power Architecture down on the bare metal (always by reprogramming the normal bus-addressable flash)I wonder how modern SoCs boot from serial devices. I didn't find too much on the net either as every system seems to rely on a combination of sd-card programming tool and a secondary bootloader, both receiving little to no attention.</p>