Hi Huazhi,
Even I also referred the same link which u provided in above query. For getting the "fw_setenv", do the following steps.
In uboot:
1) give 'env' (optional parameter) in uboot and compile it
2) this will generate the 'fw_printenv' in the U-Boot directory tools/env
3) Copy the fw_env.config file too.
3) follow the next steps from the "U-boot environment variables in linux link"
Please let me know any additional details you want for fw_printenv and fw_setenv.
Best regards
Ajith P V
