Version 4.0 is tricky. Try Archer A6 v4.0 US firmware. If that fails, OpenWrt is your only path. Check OpenWrt forums for "Realtek RTL8197F" support.
Often, yes. The TL-WDR7661 is a variant with a different external antenna design. However, always verify hardware version numbers (v1, v2, etc.) before cross-flashing. tl-wdr7660 english firmware
Introduction: The Challenge of Regional Firmware Version 4
No. Performance remains the same. However, English firmware may unlock more Wi-Fi channels (e.g., 149–165 for 5 GHz in the US). Check OpenWrt forums for "Realtek RTL8197F" support
The TP-Link TL-WDR7660 is a popular dual-band Gigabit router, known for offering exceptional value in the AC1900 class. However, if you have purchased this unit—especially from international markets like China (Mainland) or Southeast Asia—you may have encountered a frustrating problem: the management interface and firmware are locked in Chinese.