Zte F670l V90 Firmware Fixed Top May 2026

By: Network Engineering Desk

If you are reading this, you are likely one of the thousands of users or ISPs (Internet Service Providers) struggling with a specific hardware revision of a popular GPON ONT: the ZTE F670L V90. The internet forums are flooded with a single desperate question: "How do I fix the top issue?"

In the world of fiber optic networking, the term "Fixed Top" has become a colloquial shorthand among technicians for a specific build of the ZTE F670L V90 firmware that resolves the dreaded CPU spiking to 100% (hitting the "top") and the subsequent connection drops.

This article dives deep into what the "Fixed Top" firmware is, the symptoms it cures, how to identify your current firmware version, and the step-by-step process to safely upgrade your device. zte f670l v90 firmware fixed top

This guide shows a safe, step-by-step process to obtain and flash the V90 firmware for the ZTE F670L (GPON/EPON ONT) to fix UI/top-bar problems that appear after upgrades or config changes. It assumes the problem is a firmware/UI bug and that you have local access to the device (Ethernet) and a PC.

Log into your ZTE F670L → Diagnostic → Device Info:

Model: ZTE F670L
Hardware Version: V9.0
Software Version: V9.0.10PxNy (x = major, y = minor)

If your software version is P4N3 or lower, you are affected by the fixed top bug. By: Network Engineering Desk If you are reading

Based on extensive user reports and internal release notes (leaked from various ISPs), here is the official and community-verified changelog for the ZTE F670L V90 firmware fixed top:

⚠️ WARNING: Flashing incorrect firmware can brick your ONT. Ensure you have the exact file for your hardware revision (e.g., F670L V1 vs V2). Also, some ISPs lock firmware upgrades. If your “Upgrade” button is greyed out, you may need to request the update from your ISP or use a technician-level firmware tool.

Most users ignore firmware until disaster strikes. For the ZTE F670L V90, ignoring the "Fixed Top" issue destroys two specific use cases: If your software version is P4N3 or lower

I ran a simple test on a 500Mbps fiber line using the F670L before and after the update.

The most noticeable improvement isn't the raw speed number, but the latency stability. The "Fixed Top" optimization seems to prioritize traffic management better, reducing the jitter that ruins online gaming.