diff --git a/modules/libtcod-headless b/modules/libtcod-headless
index 3b4b65d..d7f2e15 160000
--- a/modules/libtcod-headless
+++ b/modules/libtcod-headless
@@ -1 +1 @@
-Subproject commit 3b4b65dc9aae7d21a98d3578e3e9433728b118bb
+Subproject commit d7f2e15e5227bb60a856e2ecb95a2e79f57b2df9
diff --git a/src/PyHeightMap.cpp b/src/PyHeightMap.cpp
index 98e3101..2b02cfa 100644
--- a/src/PyHeightMap.cpp
+++ b/src/PyHeightMap.cpp
@@ -1915,7 +1915,7 @@ PyObject* PyHeightMap::sparse_kernel_from(PyHeightMapObject* self, PyObject* arg
     if (kernel_size < 0) return nullptr;
 
     // Apply the kernel transform
-    TCOD_heightmap_kernel_transform_hm(source->heightmap, self->heightmap,
+    TCOD_heightmap_kernel_transform_out(source->heightmap, self->heightmap,
                                         static_cast<int>(kernel_size),
                                         dx.data(), dy.data(), weight.data(),
                                         min_level, max_level);
@@ -1956,7 +1956,7 @@ PyObject* PyHeightMap::sparse_kernel(PyHeightMapObject* self, PyObject* args, Py
     }
 
     // Apply the kernel transform
-    TCOD_heightmap_kernel_transform_hm(self->heightmap, result->heightmap,
+    TCOD_heightmap_kernel_transform_out(self->heightmap, result->heightmap,
                                         static_cast<int>(kernel_size),
                                         dx.data(), dy.data(), weight.data(),
                                         min_level, max_level);