Dear friend!
The factory default password of an ONT cannot be restored independently. You can restore the factory default password only by restoring the factory defaults.
Restore Factory Settings for an ONT
Use either of the following methods to restore factory settings for an ONT:
1. Choose System Tools > Restore Default Configuration from the main menu on the web page and click Default.
2. Hold down the RESET button for a long period of time (longer than 10s) to restart the ONT with factory settings.
For more information, please click on the following link:
How to obtain Huawei EchoLife ONT default username and password
How to Log in to Huawei ONT
Thank you!