Updating the firmware—the operating system of your router—is vital for several reasons:
If any step fails — power loss during NAND write, incorrect image header, or regional mismatch (e.g., trying to flash a Chinese image on an EU device) — the ONT becomes a : PON LED blinking forever, no DHCP, no serial console without soldering.
This error appears when you are trying to install firmware meant for a different hardware version (e.g., H188A V2 firmware on an H188A V6 device). Solution: Double-check your current hardware and firmware version before downloading any update.