Combine the onion powder, paprika powder and cumin, and rub the ribs with dry rub. (For best flavor refrigerate overnight so the flavors can soak into the meat.)
Mince the garlic and add the dark soy sauce, sweet soy sauce and honey. Mix until well combined and brush over the ribs. Save some of the marinade for basting during the cooking process.
Cut the ribs in half and place them in the slow cooker for 7-8 hours on low or 4-5 hours on high.
Brush the rack of ribs every hour with the remaining marinade.