Embodiments are provided for protecting boot block space in a NAND memory device connected to a host device via an SPI interface. One such method includes programming a boot block password into the NAND memory device such that the host device is required to provide the boot block password in order to access the boot block space. A counter may be provided to track the number of times the host device provides an incorrect password, permanently locking the boot block space if the counter reaches a predetermined value. A further method includes associating each of various areas of the boot block space with at least one write lock bit, setting the write lock bit to a lock enable or lock disable value, and locking or unlocking an area of the boot block space depending on the value of its associated write lock bit.