说明：  网络上能找到几个版本的DNW2，可以在linux环境下烧写友善之臂的2440和6410的板子，但是我的板子是REAL6410，经过试验，原来版本烧写U-Boot总会失败，提示 Checksum Value => MEM:3c9f DNW:0 Checksum failed. DNW download Data Error 检查之后发现DNW2的源码当中没有计算Checksum，而REAL6410的SD卡上的U-boot会对比传输过程中的Checksum是否正确，如果正确才烧写进NAND Flash。在网络上终于找到cy的修改版本，他将checksum加了进来。但是不够通用，于是仿照Ace Strong 的写法，将与开发板想关的VID PID 和RAM_BASE进行预定义，方便了不同种类开发板的修改使用。
(Network can be found on several versions of DNW2, can be programmed in a linux environment friendly arm of the 2440 and 6410 of the board, but my board is REAL6410, after testing, the original version of the program the U-Boot will always fail, suggesting Checksum Value => MEM: 3c9f DNW: 0 Checksum failed. DNW download Data Error checking the source code were discovered after DNW2 not calculated Checksum, and REAL6410 SD card U-boot on the transfer process will be compared Checksum is correct, only if the correct burning included NAND Flash. Cy on the network has finally found a modified version of checksum added that he will come. But not universal, so the wording along the lines of Ace Strong, with the development board will be off the VID PID to be predefined and RAM_BASE facilitate the development board to modify different types of use.)