Here is more info.

When you check in at Heathrow your Hold luggage should be booked all the way to Boston ( there will be a luggage sticker stuck to your boarding card so do not lose it }

On arrival in Dublin ( Aer Lingus T 2 ) you will have about an 10 min walk via transfer walkway to the Duty Free area

And Downstairs to USA Customs & Immigration pre clearance area.

You fill out your Customs form , 1 per family , & remember to declare sweets ,as food .

If you are running short of time Then they announce your name & any others who might be going to Boston and you are brought to front of line.

After your fingerprints are taken & a photo of your Iris is taken . YOU are asked " Is this your Luggage "

as displayed on a large screen ? ............ No idea what happens if you said NO

Yesterday Thursday it took us 10 min. from entering USA immigration bag security check to having our Passport

stamped and waved through to boarding gate . This was with Aer Lingus Dublin to Orlando departing at 14.20 hrs.

Yes we had gone through the Main ALL Passenger Airport security as we arrived by coach from Cork .

Hope this helps