diff --git a/speechx/CMakeLists.txt b/speechx/CMakeLists.txt
index 978a23d95..09bdb3c1e 100644
--- a/speechx/CMakeLists.txt
+++ b/speechx/CMakeLists.txt
@@ -134,7 +134,7 @@ string(STRIP ${PADDLE_COMPILE_FLAGS} PADDLE_COMPILE_FLAGS)
 # for LD_LIBRARY_PATH
 # set(PADDLE_LIB_DIRS /workspace/DeepSpeech-2.x/tools/venv/lib/python3.7/site-packages/paddle/fluid:/workspace/DeepSpeech-2.x/tools/venv/lib/python3.7/site-packages/paddle/libs/)
 execute_process(
-    COMMAND python -c " \
+    COMMAND python -c "\
 import os; \
 import paddle; \
 include_dir=paddle.sysconfig.get_include(); \
diff --git a/speechx/README.md b/speechx/README.md
index a33d484fb..a575040db 100644
--- a/speechx/README.md
+++ b/speechx/README.md
@@ -109,3 +109,7 @@ patchelf --set-soname libpaddle.so libpaddle.so
 # my gcc version is 8.2
 apt-get install gfortran-8
 ```
+
+4. `Undefined reference to '_gfortran_concat_string'`
+
+using gcc 8.2, gfortran 8.2.
diff --git a/speechx/build.sh b/speechx/build.sh
index 7655f9635..e0a386752 100755
--- a/speechx/build.sh
+++ b/speechx/build.sh
@@ -20,4 +20,4 @@ fi
 mkdir -p build
 
 cmake -B build -DBOOST_ROOT:STRING=${boost_SOURCE_DIR}
-cmake --build build -j
+cmake --build build