how to reset S5720 password?

plz find below
power off
power on
Ctrl+b

BootLoad Menu

1. Boot with default mode
2. Enter serial submenu
3. Enter startup submenu
4. Enter ethernet submenu
5. Enter filesystem submenu
6. Enter password submenu
7. Clear password for console user
8. Reboot
(Press Ctrl+E to enter diag menu)

Enter your choice(1-8): 7

Note: Clear password for console user? Yes or No(Y/N): y
Clear password for console user successfully.
Note: Choose "1. Boot with default mode" to boot, then set a new password

@MERVYNG Hi,
if you want to restoring the BootROM password, please check https://support.huawei.com/hedex/hdx.do?docid=EDOC1100037168&id=dc_cfg_bios_0085&text=Restoring%252520the%252520BootROM%252520Password&lang=en.
If you want to reset the VTY access user password, just configure another command to cover the previous password.