The latest firmware for the D-Link DSL-224 (Version 3.0.10, released November 2022) can be downloaded directly from the official D-Link FTP Server
D-Link DSL-224 Firmware Update Download Link & Installation Guide dlink dsl224 firmware update download link
Ensure you extracted the .bin file out of the downloaded .zip archive before uploading. The Power LED is solid red or blinking continuously The latest firmware for the D-Link DSL-224 (Version 3