Here is a standard boot environment configuration for GM219S devices:
Firmware Explained: The Key to Device Security & Performance firmware gm219s xpon full
If you are asking for the firmware because your device is stuck in a boot loop or you need to unlock it to work with a different ISP, please provide the exact hardware version and the ISP name written on the label. Without that, a firmware link will likely not work for your specific board. Here is a standard boot environment configuration for
Always verify the MD5/SHA256 hash. A legitimate full firmware for GM219S XPON (e.g., GM219S_XPON_FULL_v2.1.4.bin ) should have a published hash: firmware gm219s xpon full