Looking at JL0007 BOS-NRT arriving 4:15pm and departing JL0711 NRT-SIN at 6:00pm, booked on one ticket.
From research it appears both will be in T2 but I see conflicting information on security screening in that recently flights from the US will no longer need to do this.
Is the screening still needed, and is 1:45 enough time? Also, I do believe checked bags will go directly to SIN and I will not need to collect and recheck at NRT - is this correct?