diff --git a/Detector/DetCEPCv4/compact/ecal_defs.xml b/Detector/DetCEPCv4/compact/ecal_defs.xml
index 7cf7aaf375bf734656fbf7ad08b878fb3d778008..057bb5bbdee6936f385a00605c36b095ea1cbf74 100644
--- a/Detector/DetCEPCv4/compact/ecal_defs.xml
+++ b/Detector/DetCEPCv4/compact/ecal_defs.xml
@@ -43,7 +43,7 @@
   <constant name="Ecal_Barrel_Preshower" value="1"/>
   <constant name="Ecal_layer_pattern" type="string" value="0"/>
   <constant name="Ecal_end_of_slab_strategy" value="1"/>
-  <constant name="Ecal_cells_across_megatile" value="18"/>
+  <constant name="Ecal_cells_across_megatile" value="9"/>
   <constant name="Ecal_strips_across_megatile" value="1"/>
   <constant name="Ecal_strips_along_megatile" value="1"/>
   <constant name="Ecal_Endcap_Preshower" value="1"/>
@@ -55,7 +55,7 @@
   <constant name="Ecal_Slab_Plug_length" value="0*mm"/>
   
   <!-- needed only for ecal ring driver... -->
-  <constant name="Ecal_cells_size" value="10.*mm"/>
+  <constant name="Ecal_cells_size" value="10.2105*mm"/>
   <constant name="Ecal_Sc_reflector_thickness" value="0.057*mm"/>
   <constant name="Ecal_Sc_thickness" value="2.0*mm"/>
   <constant name="Ecal_Slab_Sc_PCB_thickness" value="0.8*mm"/>