diff --git a/src/calng/LpdCorrection.py b/src/calng/LpdCorrection.py
index a79b28923c0b8867f6fc61d5d14d2cc7f8c4532f..3a9ca72faf4e064a085ec4478a3a0d800218071b 100644
--- a/src/calng/LpdCorrection.py
+++ b/src/calng/LpdCorrection.py
@@ -61,7 +61,7 @@ class LpdGpuRunner(base_gpu.BaseGpuRunner):
         self.gain_amp_map_gpu = cupy.ones(self.map_shape, dtype=cupy.float32)
         self.rel_gain_slopes_map_gpu = cupy.ones(self.map_shape, dtype=cupy.float32)
         self.flatfield_map_gpu = cupy.ones(self.map_shape, dtype=cupy.float32)
-        self.bad_pixel_map_gpu = cupy.ones(self.map_shape, dtype=cupy.uint32)
+        self.bad_pixel_map_gpu = cupy.zeros(self.map_shape, dtype=cupy.uint32)
         self.bad_pixel_mask_value = bad_pixel_mask_value
 
         self.update_block_size((1, 1, 64))
@@ -101,9 +101,10 @@ class LpdGpuRunner(base_gpu.BaseGpuRunner):
         elif constant_type in (LpdConstants.BadPixelsDark, LpdConstants.BadPixelsFF):
             self.bad_pixel_map_gpu |= cupy.asarray(
                 np.transpose(
-                    constant_data.astype(np.uint32),
+                    constant_data,
                     (2, 1, 0, 3),
-                )
+                ),
+                dtype=np.uint32,
             )
         elif constant_type is LpdConstants.GainAmpMap:
             self.gain_amp_map_gpu.set(
@@ -148,6 +149,7 @@ class LpdGpuRunner(base_gpu.BaseGpuRunner):
         self.gain_amp_map_gpu.fill(1)
         self.rel_gain_slopes_map_gpu.fill(1)
         self.flatfield_map_gpu.fill(1)
+        self.bad_pixel_map_gpu.fill(0)
 
 
 class LpdCalcatFriend(base_calcat.BaseCalcatFriend):
@@ -208,21 +210,15 @@ class LpdCalcatFriend(base_calcat.BaseCalcatFriend):
             DOUBLE_ELEMENT(schema)
             .key(f"{param_prefix}.photonEnergy")
             .assignmentOptional()
-            .defaultValue(12)
+            .defaultValue(9.3)
             .reconfigurable()
             .commit(),
 
             DOUBLE_ELEMENT(schema)
             .key(f"{param_prefix}.category")
-            .displayedName("Some category")
-            .description(
-                "I don't know what this exactly is supposed to mean. Looking at "
-                "existing constants, I saw a GainAmpMap with 'category 1.0' and "
-                "'Source Energy 9.2 keV' and another one with 'category 0.0' and "
-                "'Source Energy 12.0 keV'. So maybe they're related."
-            )
+            .displayedName("Category")
             .assignmentOptional()
-            .defaultValue(1)
+            .defaultValue(0)
             .reconfigurable()
             .commit(),
         )
diff --git a/src/calng/kernels/lpd_gpu.cu b/src/calng/kernels/lpd_gpu.cu
index dfc100ea71bd18f1c7e8bde606a5c1f8fd32b4a5..38094853a6ff398eb4c297314110fce0da829476 100644
--- a/src/calng/kernels/lpd_gpu.cu
+++ b/src/calng/kernels/lpd_gpu.cu
@@ -60,7 +60,7 @@ extern "C" {
 					corrected *= rel_gain_slopes_map[gm_map_index];
 				}
 				if (corr_flags & FF_CORR) {
-					corrected /= flatfield_map[gm_map_index];
+					corrected *= flatfield_map[gm_map_index];
 				}
 			}
 		}
diff --git a/src/calng/utils.py b/src/calng/utils.py
index d0f6ceb4c9842497c6e8ba573675a4b98e5ecb70..9737de730d9c38f2845332f50bbc823c1c44d3ac 100644
--- a/src/calng/utils.py
+++ b/src/calng/utils.py
@@ -274,9 +274,9 @@ class Stopwatch:
 
     def __repr__(self):
         if self.name is None:
-            return f"{self.elapsed():.3f} s"
+            return f"{self.elapsed:.3f} s"
         else:
-            return f"{self.name}: {self.elapsed():.3f} s"
+            return f"{self.name}: {self.elapsed:.3f} s"
 
 
 class StateContext: