diff --git a/demos/grpc/download_and_install_grpc.sh b/demos/grpc/download_and_install_grpc.sh
index 5f1c2e83..8f2a1dbc 100755
--- a/demos/grpc/download_and_install_grpc.sh
+++ b/demos/grpc/download_and_install_grpc.sh
@@ -1,7 +1,9 @@
 #!/bin/sh
-INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl/
+INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl
 GRPC_SRC_DIR=$PWD/grpc
 export PATH=$PATH:$INSTALL_DIR/bin
+# Tell CMake to search for packages in Occlum toolchain's directory only
+export PKG_CONFIG_LIBDIR=$INSTALL_DIR/lib
 
 git clone https://github.com/grpc/grpc.git 
 cd grpc
diff --git a/demos/openvino/download_and_build_openvino.sh b/demos/openvino/download_and_build_openvino.sh
index 9843aed3..411809ef 100755
--- a/demos/openvino/download_and_build_openvino.sh
+++ b/demos/openvino/download_and_build_openvino.sh
@@ -36,7 +36,7 @@ build_opencv() {
       -DBUILD_opencv_python=OFF -DBUILD_PYTHON_SUPPORT=OFF \
       -DBUILD_EXAMPLES=OFF -DWITH_FFMPEG=OFF \
       -DWITH_QT=OFF -DWITH_CUDA=OFF
-    make -j
+    make -j4
     sudo make install
     popd
 }
@@ -105,6 +105,9 @@ while [ -n "$1" ]; do
     esac
 done
 
+# Tell CMake to search for packages in Occlum toolchain's directory only
+export PKG_CONFIG_LIBDIR=$PREFIX/lib
+
 if [ "$THREADING" == "TBB" ] ; then
     echo "Build OpenVINO with TBB threading"
     build_opencv
diff --git a/demos/openvino/install_cmake.sh b/demos/openvino/install_cmake.sh
index 1f7bd112..cc99829c 100755
--- a/demos/openvino/install_cmake.sh
+++ b/demos/openvino/install_cmake.sh
@@ -4,5 +4,5 @@ cd ~
 wget https://github.com/Kitware/CMake/releases/download/v3.15.5/cmake-3.15.5.tar.gz && tar xf cmake-3.15.5.tar.gz
 cd cmake-3.15.5
 ./bootstrap
-make -j
+make -j4
 sudo make install
diff --git a/demos/xgboost/README.md b/demos/xgboost/README.md
index 0823f1aa..8447a89d 100644
--- a/demos/xgboost/README.md
+++ b/demos/xgboost/README.md
@@ -2,7 +2,7 @@
 
 Step 1: Download XGBoost and its dependencies, and then build XGBoost
 ```
-./build_xgboost.sh
+./download_and_build_xgboost.sh
 ```
 When completed, the resulting XGBoost can be found in `xgboost_src` directory.
 
diff --git a/demos/xgboost/build_xgboost.sh b/demos/xgboost/download_and_build_xgboost.sh
similarity index 86%
rename from demos/xgboost/build_xgboost.sh
rename to demos/xgboost/download_and_build_xgboost.sh
index 5e246987..9abd11a5 100755
--- a/demos/xgboost/build_xgboost.sh
+++ b/demos/xgboost/download_and_build_xgboost.sh
@@ -1,6 +1,9 @@
 #!/bin/bash
 set -e
 
+# Tell CMake to search for packages in Occlum toolchain's directory only
+export PKG_CONFIG_LIBDIR=/usr/local/occlum/x86_64-linux-musl/lib
+
 # Install the dependencies
 apt-get update
 apt-get install -y python3.5
@@ -30,7 +33,7 @@ cd build
 cmake ../ \
   -DCMAKE_BUILD_TYPE=Release \
   -DCMAKE_C_COMPILER=occlum-gcc -DCMAKE_CXX_COMPILER=occlum-g++
-make -j
+make -j4
 popd
 
 # Prepare data