The short answer is The DWR-M960 uses a proprietary 4G modem (often a Quectel or Sierra Wireless) with closed-source drivers. While the main CPU may be a MediaTek SoC that OpenWrt supports, the modem interface and GPIO pins for industrial I/O are not documented. Attempting to flash third-party firmware will almost certainly brick the radio module. Stick to official DWR-M960 firmware from D-Link.
If you find one of these on eBay, update to firmware version v1.12.4 or later. The earlier builds had a memory leak in the IPv6 stack. The new one? Rock solid. Dwr-m960 Firmware
The update reset modem initialization strings or carrier settings. Fix: Re-enter your APN manually. Go to WAN > Cellular . Input your carrier’s APN (e.g., internet for T-Mobile, vzwinternet for Verizon). Toggle "Modem Reset" and reboot. The short answer is The DWR-M960 uses a