The question ,am335x's evm_sk Demo Board With two network(SDK6.0)

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The question ,am335x's evm_sk Demo Board With two network(SDK6.0):
Below are the actions of the network interface:
1. The statuses of eth0 and eth1 are both down after kernel booting.
2. Eth1 will be active as we have done a configuration “ifconfig eth1 192.168.0.10 netmask 255.255.255.0”in rc.sh
3. Then, 5s later, APP will execute system command “ifconfig eth0 up”
4. After above 3 steps, there is a chance that dual network card interface would be corrupt ;Thus , the am335x's evm_sk Demo Board could send ping packets with not receive(rx-interrupt has stop counts).
 But it will take a long time to make the issue reoccur in this way, or it may not happen.
 So, my suggestion is using the shell to make the issue occur and figure out the reason why the interface can not work normally.
Let me make it clear again, if you active eth0, and active eth1 later, the issue won’t occur, which seems like that eth0 plays a master role while eth1 acts like a slave one and affected by eth0.
But your further analysis is required. I would appreciate it if you could have a great concern on this urgent issue.                   
                            Thanks very much.