Preheat the oven to 400°. Line a loaf pan (approximately 8x4 inches) with parchment paper. Place the blackberries in a large bowl and sprinkle with the sugar, cinnamon, salt, and cornstarch. Stir to thoroughly coat and then let them sit on the counter for a few minutes while assembling the crust and topping.
Stir together the oats, coconut, flour, brown sugar, and butter. Spread half of the mixture over the parchment lined pan. Pour the berries over the crust and then sprinkle the rest of the oat mixture on top of the berries.
Bake for 30 minutes, until the crust has browned and the fruit mixture is bubbling. Serve warm with vanilla ice cream or whipped cream. Enjoy!