Using unofficial firmware (like those found on third-party forums) carries a risk of "bricking" your device. It is recommended to contact your ISP first to see if they can push a remote update. Notice:EOS Announcement for ZXHN H267A V1.0 - ZTE Support
Before searching for an update, note the exact firmware string:
If the update completes but you lose connection, you may need to re-enter your PPPoE credentials or APN settings.
If your ISP still supports the device, you can check for updates through the web management interface: Access the Interface: Connect to your modem and enter 192.168.1.1 (or your local IP) in a browser. Use the default credentials (often or found on the sticker under the device). Navigate to Updates: Maintenance Firmware Upgrade System Update Automatic Check: If your ISP provides an "Online Upgrade" feature, clicking Check for Update
If you see a "Manual Upgrade" section, that requires a file. Do not use that unless you have the exact file from your ISP.