: Only download firmware from sources you trust. If you use a third-party download, check file hashes against known good values if possible, and scan the file with antivirus software before use.
The Huawei HG8547M or Nokia G-2425G-A offers modern GPON support with better security and higher throughput.
GitHub is often a surprising source of router firmware. One user shared a link to a DG8245V-10 firmware file on MediaFire: DG8245V-10_XDSLV100R019C10SPC594B011(1).bin . This particular firmware version appears to be a V100R019 build, which is one of the later firmware families for this device.