diff --git a/bin/installexternal.sh b/bin/installexternal.sh
index f9a515b180b92b2afa0936433e5c1d987091b228..16b29a28432a5f0f2f5c8fe8870d9b704990345c 100755
--- a/bin/installexternal.sh
+++ b/bin/installexternal.sh
@@ -276,7 +276,7 @@ installOPM()
     echo "In addition, it might be necessary to set manually some"
     echo "CMake variables in the CMAKE_FLAGS section of the .opts-file:"
     echo "  -DOPM_COMMON_ROOT=/path/to/opm-common \\"
-    echo "  -Dopm-grid_PREFIX_PREFIX=/path/to/opm-grid \\"
+    echo "  -Dopm-grid_PREFIX=/path/to/opm-grid \\"
     echo "  -Dopm-common_PREFIX=/path/to/opm-common \\"
     echo "  -Dopm-core_PREFIX=/path/to/opm-core \\"
     echo "  -Dopm-material_PREFIX=/path/to/opm-material \\"
diff --git a/patches/README b/patches/README
index e0378900095d6f21fd0481ee1f1ffffcb4b77a58..ddf06ffa5bb1a0a4bf4a8eaa3611e42b32c1b010 100644
--- a/patches/README
+++ b/patches/README
@@ -15,7 +15,7 @@
   patch -p1 <../dumux/patches/opm-common-2016.04.patch
   In addition, it might be necessary to set manually some CMake variables in the
   CMAKE_FLAGS section of the .opts-file:
-    -DOPM_COMMON_ROOT=/path/to//opm-common/ \
+    -DOPM_COMMON_ROOT=/path/to/opm-common/ \
     -Dopm-grid_PREFIX=/path/to/opm-grid \
     -Dopm-common_PREFIX=/path/to/opm-common \
     -Dopm-core_PREFIX=/path/to/opm-core \