I try to update the firmware from 386.2.4 to 3.2, on AC-68P to which I'm logged in remotely. As soon as I press the button, I see "Please wait, applying settings..." . In about 30 seconds remote router stop responding to ping for 2 more minutes, then resumes. I re-logon, and the log shows that it has restarted, but the version is still 2.4. How to find out why it does not update?