A methodology for efficiently copying data is presented. An internal controller RAM is multiplexed between storing existing RAM data such as look up table data) and storing copy back data with respect to a flash memory. The data in the controller RAM is temporarily stored in a free space of the flash memory. The data of the flash memory, which is to be copied, is read from a source page and is stored in the free space of the controller RAM, and from there, the data is written to a destination block of the flash memory. After completion of the copy back operation, the data of the controller RAM that was moved to the free space is retrieved for storage back in the controller RAM.