Look at the sticker on the physical router. Use the original default factory username and password to log in. Post-Update Best Practices
Log back into the interface. Go to the configuration section and manually re-enter your ISP's VDSL settings (VLAN ID, Username, and Password). Alternatively, restore your saved backup file. Firmware reset factory defaults. Huawei Hg658 V2 Firmware Download
To help find the exact firmware for your needs, let me know: Who is your ? What is your current firmware version string? Look at the sticker on the physical router