Initial software: 6.4x.x (not sure what the exact version was)
Upgraded to: 7.6 (POE started at boot with no eth connections)
Since: reverted to 6.49.7 and 6.48.6 and no luck turning it off.
Then resorted to netinstall and no luck either.
I have thoroughly cleaned the board and visually inspected the port for dust but nothing.