I flew LHR-HND and HND-JFK in F last week. Only issue I had was the in-seat power on both flights (different aircraft) was unable to charge my laptop or my IPad/iPhone (latter two through the USB port). The green light was on and my laptop cord would briefly indicate it was getting power, but then it stopped working. I've never had an issue with JAL before and have never had an issue on any other airline with the same laptop, iPhone, iPad.