Mix brown sugar and flour in a saucepan.
Add water, vinegar, soy sauce, ketchup, ginger, and garlic powder.
Cook and stir over medium heat until boiling and thickened.
Layer ribs in a 4-6 quart crockpot, spooning sauce over each layer.
Cover and cook on low for 10-12 hours or on high 5-6 hours until ribs are tender.