diff --git a/src/calng/JungfrauCorrection.py b/src/calng/JungfrauCorrection.py
index 028e2678d3984ade9a6fb3a15b80612f176e7219..77cd6dcbf4a8ea241dc891835a017e8c11f81a26 100644
--- a/src/calng/JungfrauCorrection.py
+++ b/src/calng/JungfrauCorrection.py
@@ -71,7 +71,7 @@ class JungfrauGpuRunner(base_gpu.BaseGpuRunner):
         # TODO: avoid superclass creating cell table with wrong dtype first
         self.cell_table_gpu = cupy.empty(self.memory_cells, dtype=cupy.uint8)
         self.input_gain_map_gpu = cupy.empty(self.input_shape, dtype=cupy.uint8)
-        self.map_shape = self.input_shape + (3,)
+        self.map_shape = (self.constant_memory_cells, self.pixels_y, self.pixels_x, 3)
         # is jungfrau stuff gain mapped?
         self.offset_map_gpu = cupy.zeros(self.map_shape, dtype=cupy.float32)
         self.rel_gain_map_gpu = cupy.ones(self.map_shape, dtype=cupy.float32)