Before downloading any files, you must identify your specific hardware revision. Firmware for revision D4, for example, is incompatible with others.

Look for the string "H/W Ver:" followed by a code (e.g., A1, C1, D4).

Check the sticker on the bottom or back of the router.

Alternatively, log in to the web management page; the version is often displayed in the top right corner or under "System Info". How to upgrade the firmware on your D-Link router