With ECC, NAND can achieve bit error rates (BER) that are comparable with NOR, which is commonly used as a booting device. Applications that use NAND typically copy the booting code to DRAM and execute from DRAM. For more information, read Tech Note 29-16, which is geared to a specific processor, but the concepts can be applied generally. TN-29-19 is a very useful technical note on the general concepts of NAND.