Hi Teddy Bear,
I found one bug about the Samba File Sharing with authentication has been enabled then disabled and it's made File sharing w/o password was failed.
1.Go to File sharing with authentication (have password) -> save.
2.Tried \\192.168.1.254\ with Password -> Test Passed.
3.Go to File sharing without authentication (no password) -> save.
4.Tried \\192.168.1.254\ without Password -> Test Failed.
5.Tried use command "net use * /del /yes" for clear client PC network share password
and then try connect to \\192.168.1.254\ -> Test Failed.
Configure as below:
TomatoUSB Version: Tomato Firmware v1.27.8747 ND USB vpn3.6
AP Model: ASUS WL-520GU