Go to > System Management > Software Upgrade .
The community quickly dubbed the “golden master.” If you have 2021c, you can manually downgrade by uploading the 2021b .trx file via the bootloader (hold reset while powering on, then navigate to 192.168.1.1 with TFTP).
| Feature / Issue | Firmware 2019–2020 | Firmware 2021 (B11/B13) | |----------------|--------------------|--------------------------| | Default Wi-Fi security | WPA2 only | WPA2/WPA3 | | Band locking | Hidden/disabled | GUI-enabled (most variants) | | Security CVEs | Several unpatched | Critical ones fixed | | IPv6 support | Basic | Full DHCPv6/PD | | SMS via web | Partial | Full | zte h2640 firmware 2021
ZTE has since removed the 2021 files from their public FTP to push newer (and arguably less stable) 2023 builds. However, the Internet Archive and several OpenWrt forums have preserved them.
The 2021 firmware tightened security, making standard user accounts less powerful. To change advanced settings like DNS or bridge mode, you often need "Supervisor" access. Go to > System Management > Software Upgrade
: Optimising high-speed wireless connectivity for modern devices. Traffic Prioritisation
Occasionally, applying a major firmware update like the 2021 release can cause configuration conflicts with older settings stored in the router's non-volatile memory (NVRAM). If you experience anomalies after an update, follow these optimization steps. Perform a Factory Reset However, the Internet Archive and several OpenWrt forums
Type 192.168.1.1 (or 192.168.0.1 , depending on your ISP's default configuration) into the address bar and press Enter.
Full support for Orthogonal Frequency-Division Multiple Access (OFDMA) and Target Wake Time (TWT) to reduce battery drain on connected mobile devices. Physical Interface: 1 x Gigabit Ethernet WAN port 4 x Gigabit Ethernet LAN ports 1 x USB 2.0 port for local storage or print servers 1 x FXS VoIP port 2. Core Functional Modules
: General software and document maps are maintained on the ZTE Support Portal . ZXHN H2640 - ZTE Italia