diff --git a/docker/Dockerfile b/docker/Dockerfile
index d9eace4..3b91acf 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -53,7 +53,8 @@ RUN mkdir dawn-source \
 ## main package — build Geant4 from submodule source
 ADD minicalosim/lib/geant4 /tmp/geant4-src
 
-RUN cmake \
+RUN rm -f /tmp/geant4-src/.git && \
+    cmake \
         -S /tmp/geant4-src \
         -B /tmp/geant4-build \
         -DCMAKE_INSTALL_PREFIX=/opt/geant4-v11.1.2 \
diff --git a/docker/Dockerfile-cpu b/docker/Dockerfile-cpu
index b6d00ed..2c60cf0 100644
--- a/docker/Dockerfile-cpu
+++ b/docker/Dockerfile-cpu
@@ -53,7 +53,8 @@ RUN mkdir dawn-source \
 ## main package — build Geant4 from submodule source
 ADD minicalosim/lib/geant4 /tmp/geant4-src
 
-RUN cmake \
+RUN rm -f /tmp/geant4-src/.git && \
+    cmake \
         -S /tmp/geant4-src \
         -B /tmp/geant4-build \
         -DCMAKE_INSTALL_PREFIX=/opt/geant4-v11.1.2 \
diff --git a/docker/Dockerfile-mini b/docker/Dockerfile-mini
index 941e968..004314b 100644
--- a/docker/Dockerfile-mini
+++ b/docker/Dockerfile-mini
@@ -19,7 +19,8 @@ RUN python3 -m pip install --upgrade pip && \
 # Geant4 — build from submodule source (batch mode only, no visualization, no multithreading)
 ADD minicalosim/lib/geant4 /tmp/geant4-src
 
-RUN cmake \
+RUN rm -f /tmp/geant4-src/.git && \
+    cmake \
         -S /tmp/geant4-src \
         -B /tmp/geant4-build \
         -DCMAKE_INSTALL_PREFIX=/opt/geant4-v11.1.2 \