I've just upgraded my modem to the HG659b. Everything is working fine except my Yealink phones connected via ethernet are returning register fail. I have the iphone app using the same account credentials which is working fine. I've tried rebooting but no joy. Is there a setting on the modem that needs to be changed to allow the register to work. I notice that the modem has a special voip function and wonder if that is causing the issue.