In a small screw-top jar combine cumin, brown sugar, chili powder, coriander, cinnamon, red pepper flakes, and black pepper. Cover and shake well to combine. Remove 2 tablespoons for this recipe. Store remaining rub, covered, at room temperature for up to 1 month.
Preheat oven to 325 degrees F. Trim fat from pork roast. Rub 2 tablespoons seasonings blend over all surfaces of the pork roast. Place roast on a rack in a shallow pan and insert an oven-going thermometer. Roast for 1 to 1 1/2 hours or until thermometer registers 155 degrees F. Remove from oven. Cover meat with foil; let stand 15 minutes. The temperature of the meat after standing should be 160 degrees F.