After TL-MR3020 is upgraded to new firmware 120817 from older version, the wireless network would be secured by the default pre-encryption password. Below are the steps about how to find and change the default password.
Connect your computer to TL-MR3020’s Ethernet Port with an Ethernet cable. Then open your web browser and type in http://192.168.0.254. A window will pop up and ask for username and password. By default, they are both admin.
After Login, you will see TP-LINK Management Page. Please go to Wireless->Wireless Security. On this page, the pre-encryption will be found. See below:
Change this wireless password to your favorite one then Click Save. Reboot is needed to take effect.
Note: if you reset the device to factory default, you will have to do all the above steps again to change the wireless password to your own one.