Dragino Yun Shield firmware update using Hercules

Hi,

I have stacked my Dragino Yun Shield on top of Uno. I have connected once to my yun shield
with ip 192.168.240.1 and configured the network properties. I did not change dragino authentication.
I have gave my routers SSID, wifi password and encryption there. then restarted the device to configure and save settings.

next time I boot up I could not access the ip 192.16.240.1.
I have pressed reset button 5 secs and also later for 30 secs.

If I powered up my yun shield it shows lan, wan, sys LEDs blinking all together.
Some times the sys and fwr LEDs only blink.

I have tried to follow below link of dragino to recover, but bad luck.

http://wiki.dragino.com/index.php?title=Yun_Shield#How_to_recover_the_Yun_Shield_in_case_firmware_crash

I have disabled windows firewall and changed the ip and mask as it says.
connected Yun with LAN. the network cable shows unplugged. yun is powered up.
what did i miss. Someone please help. Do I need to provide anything to confirm what is happening to my
Yun shield?

Regards,
Tajuddin