The plane was travelling from Toronto to Poland when it was diverted to the Icelandic capital about 1,700 miles short of its destination.
The plane's antenna is used to transmit airplane identification information. LOT sent parts and personnel to Iceland to fix the problem, Boeing spokesman Doug Alder said in an emailed statement. The airplane maker was ready to help if needed, he said.
Boeing's 787 Dreamliner, the world's first commercial plane made mostly of lighter-weight composite materials, has been plagued by a series of problems since its introduction in September 2011. Even before Sunday's incident LOT had reported technical problems and demanded that Boeing try to solve a potential safety threat.
The worldwide fleet of 787 planes was grounded in January after lithium-ion batteries that overheated or caught fire following an incident on a flight by the Japanese airline All Nippon Airways. Flights resumed four months later after a revamped battery system was installed. In July, a Boeing 787 operated by Ethiopian Airlines caught fire while parked at London's Heathrow airport.
Representatives of LOT could not be reached.