各位大牛，急需帮忙：
就是我sdk6.0已经可以烧写了，按照那个方法烧写sdk7.0也能烧写好，可是让板子自己启动的时候u-boot阶段出现了问题。log如下：
reading uEnv.txt
** Unable to read file uEnv.txt **
reading uImage
4117904 bytes read in 406 ms (9.7 MiB/s)
Booting from mmc ...
## Booting kernel from Legacy Image at 80007fc0 ...
Image Name: Linux-3.12.10-ti2013.12.01
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 4117840 Bytes = 3.9 MiB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... OK
XIP Kernel Image ... OK
OK
Starting kernel ...
请问这个uEnv.txt 如何生成呢？