are you able to ping the xenon server or repeater's IP from the notebook connected to the router wifi? Hope about plugging the xenon server to the repeater's Ethernet port ?

Here is an instruction for slow speed issue. You can refer it to change some settings. http://www.tp-link.com/en/faq-1077.html

TP-Link has some limitation to upgrade and downgrade the firmware to different version. If the last version is un version but the current one is EU version, you may not downgrade the firmware....

Yes, you can change the extended 2.4G ssid by going to Settings-Wireless-Extended Network, but the password can't be changed, it must be the same as your host network.

Glad to help you out!;)

Is your router also TD-W8961ND V3? You can check whether the IP address is saved before you reboot the router by going to another option then go back. If the IP address is back to 192.168.1.1, which...