A method and apparatus for booting a microprocessor system using a serial (e.g., NAND-type) flash memory array having a random-access (parallel, e.g., NOR-flash type) interface. The method includes loading a boot code loader stored in the serial (e.g., NAND-type) flash memory array into a RAM when power is turned on, according to a routine of a read-only memory (ROM) of the microprocessor; loading boot code stored in the serial flash memory into an internal or external (main) RAM of the microprocessor according to the boot code loader; loading application code stored in the serial flash memory into the main (RAM) memory according to the boot code; and executing the application code. The system may be manufactured at a low cost compared to NOR-Flash based systems, while ensuring flexibility of a microprocessor.