Step 2: Backstrap.
Make a cut down each side of the backstrap at the vertebrae, from pelvis to neck, keeping knife on the edge of the vertebrae. Make the cut deep to the bone sticking out from the vertebrae. Along the ribs, insert the knife until it meets the vertebrae cut. Work the knife down along the ribs until the whole backstrap is loose. Cut ends of backstrap and remove. Set aside in cooler.