Next is the boot loader. Analog Devices has the source at http://uboot.sourceforge.net, under active development. They can be located by going to https://blackfin.uclinux.org/doku.php site to find patches for the boot loader. The boot loader can understand environment variables, do a serial download via Ethernet, or it can extract an image from its own flash memory. It has flash management capability as well. If an image has to be put in the flash memory, something must be done to it to make uboot understand. It needs to be wrapped in a header and the "makeimage" command there. An example has been extracted which is used to take the linux.dxe elf image and wrap it such that the boot loader can understand it.