An introduction to the ARM boot sequence on Boot ROM based embedded platforms. Covers what happens at power-on reset, how the Boot ROM initializes clocks and stacks, how it probes boot media (NOR/NAND flash, UART/USB), and when control is passed to a software bootloader. Key differences between NOR XiP (execute-in-place) and NAND (RAM-loading) are explained, along with bad block management requirements. The software bootloader's role in initializing DDR memory and loading the OS is also outlined.
3 Impressions