Because official support is non-existent, finding the correct English firmware requires searching community archives. The best resources are:
Disclaimer: Modifying router firmware may void your warranty and is done at your own risk. Always verify hardware versions before proceeding. tl-wdr7660 english firmware
The TP-Link TL-WDR7660 Go to product viewer dialog for this item. Because official support is non-existent
The (also known as the Archer A7 in some markets) is primarily a model released for the Chinese domestic market. Because it is a region-specific device, there is no official English firmware available from TP-Link that can be directly flashed onto the Chinese hardware. tl-wdr7660 english firmware