The Boeing 777 is fully capable of flying directly over the North Pole. The Airbus product, on the other hand, is not. Apparently on the 'Bus, the instantaneous change in heading from 360 degrees to 180 degrees drives the APFDS (and consequently the autopilot) squirrelly. My carrier chooses not to directly cross the true North Pole with 777 out of conservative flight planning.
'Taco