Preheat oven to 425 degrees. Mix sugar, cornstarch, salt and cinnamon, and sprinkle over blueberries. Line pie dish with 1 pie crust. Pour berry mixture into the crust, and dot with butter. Cut remaining pastry into 1/2- to 3/4-inch-wide strips, and make lattice top. Crimp and flute edges.

Bake pie on lower shelf of oven for about 50 minutes, or until crust is golden brown.