Never update via Wi-Fi. Connect your PC to one of the router’s LAN ports using an Ethernet cable .
Installing firmware for a different revision (like C1, C4, or U1) can permanently damage (brick) your device. 2. Download the Correct Firmware
For revision T3 , the latest verified version is typically 1.0.7 (released in 2013). 3. Preparation Steps
You can find the specific T3 files on the D-Link Russia Downloads Page .
Before downloading, you confirm your device is indeed the T3 revision. Check the sticker on the bottom of the router. Look for the line H/W Ver.: T3 .