Reuters has this article on possible ETOPS consequences of FAA findings. In the past aircraft needed a good reliability record to apply for longer ETOPS.
(Reuters)
As Boeing works to regain permission for its 787 Dreamliner to resume flights, the company faces what could be a costly new challenge: a temporary ban on some of the long-distance, trans-ocean journeys that the jet was intended to fly.
Aviation experts and government officials say the Federal Aviation Administration may shorten the permitted flying time of the 787 on certain routes when it approves a revamped battery system.
Boeing 787 faces new risk: limits on extended range: sources | Reuters
Not so long ago Boeing was working towards 787 ETOPS330.
Boeing nears 787 GEnx and 330min ETOPS certification
For illustration I generated an indicative ETOPS90 chart from
Great Circle Mapper. I have no idea what limitation the FAA would apply, if at all, for the 787 to re-enter service.
http://www.gcmap.com/map?P=LAX-NRT,+...X=720x360&PM=*