Before searching for an update, note the exact firmware string:

Search for "ZXHN H267A" or look under "Modem/Router Firmware."

Finding a direct download link for the ZXHN H267A V10 can be highly challenging for everyday users. ISP-Locked Custom Firmware

Suppose, however, you are tenacious. You dig through Russian forum 4pda, a Brazilian tech Facebook group, or a Vietnamese networking subreddit. You finally find a user who posts a link: http://some-obscure-server.com/zte/h267a/v10/update.bin . You feel the rush of victory.