Because this is an older ADSL modem, ZTE often provides firmware updates through regional ISP partners or their global support portals. Official Support: ZTE Global Support Center ZTE Enterprise Portal to search by your specific hardware revision. ISP Portals:

Finding verified firmware for the series can be challenging because it is an older ADSL modem. While some "helpful reviews" or forum posts may claim to have verified links, you should prioritize official channels to avoid security risks like malware or bricking your device. How to Safely Update Your ZTE ZXV10 W300

Verification: Look for an official .bin or .trx file with a release note signed by your ISP.

Look at the sticker on the bottom of your modem. Locate the field labeled "Hardware Version" . It must match the firmware you download (e.g., if your sticker says V1.0, you cannot use V2.0 firmware).