As we know, the bootloader stores its configuration into an area of the flash called the environment. The environment is basically stored as a sequence of null-terminated strings, with a little header containing a checksum at the beginning. Using the “printenv”, “setenv” and “saveenv” commands in U-Boot, while this environment can easily be manipulated. It is sometimes desirable to be able to generate a binary image of an environment that can be directly flashed next to the bootloader, kernel and root filesystem into the device’s flash memory.

In order to modify the U-Boot environment variables from user space, the program called “mkenvimage” is needed, this program can be generated from the U-Boot sources, follow the instructions in the tools/env/README file.

This will get the program “mkenvimage”, the program is executed in host computer, not the target board. The text file “uboot-env.txt” describing the environment is needed like:

Then use mkenvimage as follows:

The -s option allows to specify the size of the image to create. It must match the size of the flash area reserved for the U-Boot environment.

Before using the new uboot-env.bin, the old bin file should be restored by the following commands:

Then, flashing the new bin file in /dev/mtd7 by the following commands:

Or, the Lauterbach Debugger is also a good tool to flash the Hyper-Flash.

创建Uboot 环境变量 bin 文件

原文：https://www.cnblogs.com/hutiann/p/11431185.html