The short answer is for most variants. The ZTE F680 uses a proprietary ZTE chipset (ZX279127) with very limited open-source driver support. Unlike Broadcom or Qualcomm routers, the F680 lacks a community-driven custom firmware ecosystem.
Pluggable source adapters
Unlike a PC, you cannot simply reinstall Windows from a USB stick on a router. Recovery requires a serial console (UART) or a JTAG programmer, which is difficult for the average user. Zte F680 Firmware
Then, a single green LED flickered. Then two. Then all four. The short answer is for most variants