The default.nx2 file packages different hex files built off the NX2LP code. The default.nx2 file provided with the CD or that which is downloaded from the website, packages the hex file for 512byte page NAND Flash chip and 2K page NAND Flash chip together. So, when the Program Device button is clicked in the NX2LP Programming Utility, upon checking the page size of the NAND Flash chip, the pertinent code is downloaded onto the NAND Flash chip. One can build their own .nx2 files using the buildnx2 application. The NX2 currently supports interface only with 512byte and 2K page sizes.