"I’m flying First Class. And surfing too
You can surf the net free of charge in Lufthansa First Class on all long-haul flights. You will receive a voucher on board for this with your personal access code."

I am in F BLR-FRA and then connecting FRA-EWR in C, Will this code work for 24 hours, i.e. the free code I get on the first flight will work on the 2nd? I plan to sleep on the first flight, so if not for 24 hours can i save the code and use it on the 2nd or is it specific to the flight I am given it on?