Because the and MAC chip are shared but configured differently, a pure software change may not fully work.
If you only want the without changing function: firmware huawei hg8245h gpon to epon
Not all HG8245H units are created equal. To convert GPON to EPON, your device must have a (e.g., HPSF2120, RTXM169-502, or similar). Many Chinese-market HG8245H units come with GPON-only modules. Because the and MAC chip are shared but