In a small mixing bowl, stir together the salt, sugar, chili powder, cumin, paprika, onion, cayenne, black pepper and white pepper. Cut the ribs in 4 rib pieces and rub all over with the dry rub mixture. Brush evenly with 1 cup of the sauce and place standing up in the pressure cooker. Pour a half cup of the sauce over the top, cover and cook on high for 27 minutes. Release pressure and let ribs cool, then refrigerate 8 hours or overnight.
Preheat the grill to medium-high and grill 8 minutes, turning to char evenly while basting with the remaining sauce. Serve warm.
Recipe by The Tennessee Magazine at https://www.tnmagazine.org/stick-to-your-ribs-2/