Heat a large cast-iron skillet over medium. Add bacon; cook, stirring often, until crisp, about 8 minutes. Drain on paper towels; reserve drippings in skillet.
Increase heat to medium-high. Add corn and squash to drippings; cook until lightly charred and al dente, about 2 minutes. Transfer to a large bowl; cool 10 minutes. Add onions, eggs, cornmeal, pepper, 1/4 teaspoon salt, and cooked bacon to corn mixture; stir to combine. Let mixture stand 5 minutes, stirring occasionally.
Stir together yogurt, maple syrup, turmeric, and remaining 1/8 teaspoon salt in a small bowl. Set aside.
Heat skillet over medium. Drop batter by 1/4-cupfuls into skillet, flatten slightly with a spatula, and cook until firm and browned on each side, about 2 minutes per side. Serve with turmeric-yogurt mixture.