9970 seems to support FAT/FAT32/NTFS only... http://www.tp-link.sg/faq-603.html

Confirmed with TP-LINK before, it's also 32.

There could be a compatible issue when wirelessly bridging between 2 routers, however, you can have a try http://uk.tp-link.com/faq-447.html

The previus posts are 8968 V1, how about yours? What is the hardware and firmware version? If the WLAN light also went off when wifi stoped working? Or the light still on but SSID won't show up, or...

Did you setup the TD-W8970 correctly and if there is a WAN IP address on its status page? How about the wireless connection or the LAn connection on another PC?

There is no option to change the IP from deco app.