Official firmware for the TP-Link Archer C6 V3.20 varies by region. You must download the version matching your specific device's region (e.g., US or EU) to avoid bricking the router. TP-Link Community Direct Firmware Download Links
You can update your router using the web interface or the TP-Link Tether mobile app. Method 1: Using the Web Management Page (Recommended)Official firmware for the TP-Link Archer C6 V3
Set PC IP to 192.168.0.66.
Hold Reset button while powering on for 15 seconds.
Upload correct firmware via http://192.168.0.1.
You can upgrade your firmware using the web interface or the TP-Link Tether app. Method 1: Web Management Page [OpenWrt Wiki] TP-Link Archer C6 v3 Set PC IP to 192