diff --git a/bin/qgis/smoderp2d-plugin/scripts/build_package.sh b/bin/qgis/smoderp2d-plugin/scripts/build_package.sh
index ce47f329..fd3395b6 100755
--- a/bin/qgis/smoderp2d-plugin/scripts/build_package.sh
+++ b/bin/qgis/smoderp2d-plugin/scripts/build_package.sh
@@ -6,7 +6,10 @@ source $VENV/bin/activate
 
 script_dir=$(realpath $(dirname $0))
 echo $script_dir
+### install released SMODERP2D version
 pip3 install smoderp2d
+### or from git
+# (cd ../../.. ;pip3 install .)
 
 pv=$(python3 -V | cut -d' ' -f 2 | cut -d'.' -f 1,2)
 LIB=$VENV/lib/python$pv/site-packages
diff --git a/bin/qgis/smoderp2d-plugin/smoderp_2D_dockwidget.py b/bin/qgis/smoderp2d-plugin/smoderp_2D_dockwidget.py
index 4cef0a8f..570c04c5 100644
--- a/bin/qgis/smoderp2d-plugin/smoderp_2D_dockwidget.py
+++ b/bin/qgis/smoderp2d-plugin/smoderp_2D_dockwidget.py
@@ -79,7 +79,8 @@ def run(self):
                     for line in islice(fin, 1, 2):
                         if 'SMODERP2D patch applied' not in line:
                             raise ImportError(
-                                'Your GRASS GIS installation needs to be fixed. Check the '
+                                'There is a bug affecting the plugin functionality. Update QGIS to '
+                                'version 3.34.10/3.38.2 or higher, or apply the fix manually. Check the '
                                 '<a href="https://storm-fsv-cvut.github.io/smoderp2d-manual/providers.html#known-issue">documentation</a>.'
                             )
             self.runner.create_location(QgsProject.instance().crs().authid())
diff --git a/smoderp2d/providers/grass/__init__.py b/smoderp2d/providers/grass/__init__.py
index 8b1d015d..7a9e1b01 100644
--- a/smoderp2d/providers/grass/__init__.py
+++ b/smoderp2d/providers/grass/__init__.py
@@ -111,6 +111,8 @@ def __init__(self, log_handler=GrassGisLogHandler):
         os.environ['GRASS_OVERWRITE'] = '1'
         # be quiet
         os.environ['GRASS_VERBOSE'] = '0'
+        # allow to run r.hydrodem also when compatibility test fails
+        os.environ['GRASS_COMPATIBILITY_TEST'] = '0'
 
         # define storage writer
         self.storage = GrassGisWriter()
diff --git a/smoderp2d/providers/grass/data_preparation.py b/smoderp2d/providers/grass/data_preparation.py
index f491d29e..15e969c2 100644
--- a/smoderp2d/providers/grass/data_preparation.py
+++ b/smoderp2d/providers/grass/data_preparation.py
@@ -32,9 +32,19 @@ def __init__(self, options, writer):
         super(PrepareData, self).__init__(writer)
 
         # install r.hydrodem if not available
+        install_ext = False
         ext = Module('g.extension', flags='a', stdout_=PIPE)
         list_ext = ext.outputs.stdout.splitlines()
         if 'r.hydrodem' not in list_ext:
+            install_ext = True
+        else:
+            # try to run the module
+            try:
+                Module("r.hydrodem", run_=False)
+            except Exception:
+                install_ext = True
+        if install_ext:
+            Logger.info("Installing r.hydrodem extension...")
             Module('g.extension', extension='r.hydrodem')
 
     def __del__(self):