Place pork butt, onion, 5 cloves garlic, and 1 tablespoon salt in a large pot; cover with water. Simmer mixture over medium heat until pork is very tender, about 3 hours. Discard onion and garlic. Strain and shred meat, reserving liquid.

Heat a skillet over medium-high heat. Cook and stir California chile pods and New Mexico chile pods in the hot skillet until toasted and fragrant, 2 to 3 minutes. Rinse chile pods. Bring a pot of water to a boil and add chile pods; boil until chile pods are slightly softened, about 3 minutes. Drain and cool chile pods.

Blend 1 cup pork broth, 1 cup water, chile pods, 1 tablespoon salt, 3 cloves garlic, and cumin together in a blender until smooth. Stir pork meat and chile sauce together in a bowl.

Melt 1/2 cup lard in a large pot over medium heat. Stir flour into melted lard until browned and fragrant, about 5 minutes. Stir pork-chile sauce mixture into flour mixture, adding more salt if needed.

Remove silk and debris from corn husks and soak in boiling water, 30 minutes to 1 hour. Drain and place on a work surface; cover with a clean, damp towel.

Mix masa, 1 pound lard, 1 cup reserved pork broth, baking powder, and salt in a large pan until mixture is fluffy and holds together.

Select 1 wide corn husk or 2 small ones. Spread about 2 tablespoons masa mixture onto corn husk, spreading to the sides and about 2 inches from the bottom and 1/4 inch from the top. Spoon 1 to 2 tablespoons pork mixture down the center of masa mixture. Fold sides of husk together, 1 over the other. Fold the bottom of husk over seam of 2 folded sides. Repeat with remaining husks and filling.

Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Bring water to a boil. Add tamales and cook until filling is heated through and set, 1 to 2 hours. Let tamales rest for 30 minutes before serving.