A walkaround: assign a static IP to eth0 for nfs remotely start system

I tried to boot the target board "armsys6410" by remotely loading a root file system through nfs. According to the given user manual, the argument of u-boot is

setenv bootargs "root=/dev/nfs nfsroot=192.168.253.2:/hom/localhost/armsys6410/root/ ip=192.168.253.12:192.168.253.2:192.168.253.2:255.255.255.0:armsys.hzlitai.com:eth0:off console=ttySAC0,115200"

Here /home/localhost/armsys6410/root is the file system located at my host machine. 192.168.253.12 is the static ip of board, while 192.168.253.2 should be static ip of host machine.

The problem of mine is I cannot fix a static IP to eth0, when I use at the same time wlan0. I didn't find a ultimate solution for the problem. Here is just walkaround:

Precondition: minicom has been correctly configured, serial port and cross-over cable have been correctly connected between host and target.

1) reset the board
2) press any key to suspend the booting (I use u-boot here)
3) >sudo ifconfig eth0 192.168.253.2 netmask 255.255.255.0 up
4) in minicom, input "reset"


Then the board can start with given root file system