diff --git a/demos/grpc/download_and_install_grpc.sh b/demos/grpc/download_and_install_grpc.sh
index ea5c9169..5f1c2e83 100755
--- a/demos/grpc/download_and_install_grpc.sh
+++ b/demos/grpc/download_and_install_grpc.sh
@@ -1,6 +1,7 @@
 #!/bin/sh
-install_dir=/usr/local/occlum/x86_64-linux-musl/
-export PATH=$PATH:$install_dir/bin
+INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl/
+GRPC_SRC_DIR=$PWD/grpc
+export PATH=$PATH:$INSTALL_DIR/bin
 
 git clone https://github.com/grpc/grpc.git 
 cd grpc
@@ -12,54 +13,52 @@ then
 fi
 
 # Install c-ares
-cd third_party/cares/cares
+cd $GRPC_SRC_DIR/third_party/cares/cares
 git submodule update --init .
 git checkout tags/cares-1_15_0
 mkdir -p build
 cd build
 cmake ../ \
 	-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=occlum-gcc \
-	-DCMAKE_INSTALL_PREFIX=$install_dir
+	-DCMAKE_INSTALL_PREFIX=$INSTALL_DIR
 if [ $? -ne 0 ]
 then
   echo "cares cmake failed"
   exit 1
 fi
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "cares make failed"
   exit 1
 fi
 make install
-cd ../../../..
 
 # Install zlib
-cd third_party/zlib
+cd $GRPC_SRC_DIR/third_party/zlib
 git submodule update --init .
 git checkout tags/v1.2.11
 mkdir -p build
 cd build
 cmake ../ \
 	-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=occlum-gcc \
-	-DCMAKE_CXX_COMPILER=occlum-g++ -DCMAKE_INSTALL_PREFIX=$install_dir \
+	-DCMAKE_CXX_COMPILER=occlum-g++ -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR \
 	-DCMAKE_NO_SYSTEM_FROM_IMPORTED=TRUE
 if [ $? -ne 0 ]
 then
   echo "zlib cmake failed"
   exit 1
 fi
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "zlib make failed"
   exit 1
 fi
 make install
-cd ../../..
 
 # Install protobuf
-cd third_party/protobuf
+cd $GRPC_SRC_DIR/third_party/protobuf
 git submodule update --init .
 git checkout tags/v3.10.0
 cd cmake
@@ -68,7 +67,7 @@ cd build
 cmake ../ \
 	-Dprotobuf_BUILD_TESTS=OFF -DBUILD_SHARED_LIBS=TRUE \
 	-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=occlum-gcc \
-	-DCMAKE_CXX_COMPILER=occlum-g++ -DCMAKE_INSTALL_PREFIX=$install_dir \
+	-DCMAKE_CXX_COMPILER=occlum-g++ -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR \
 	-DCMAKE_NO_SYSTEM_FROM_IMPORTED=TRUE
 
 if [ $? -ne 0 ]
@@ -77,27 +76,26 @@ then
   exit 1
 fi
 
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "protobuf make failed"
   exit 1
 fi
 make install
-cd ../../../..
 
-cp $install_dir/bin/protoc /usr/bin
+cp $INSTALL_DIR/bin/protoc /usr/bin
 
 # Install gRPC
-cd cmake
+cd $GRPC_SRC_DIR/cmake
 mkdir -p build
 cd build
 cmake ../.. \
 	-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=occlum-gcc \
 	-DCMAKE_CXX_COMPILER=occlum-g++ -DgRPC_INSTALL=ON -DgRPC_PROTOBUF_PROVIDER=package \
 	-DgRPC_ZLIB_PROVIDER=package -DgRPC_CARES_PROVIDER=package \
-	-DgRPC_SSL_PROVIDER=package -DCMAKE_PREFIX_PATH=$install_dir \
-	-DCMAKE_NO_SYSTEM_FROM_IMPORTED=TRUE -DCMAKE_INSTALL_PREFIX=$install_dir
+	-DgRPC_SSL_PROVIDER=package -DCMAKE_PREFIX_PATH=$INSTALL_DIR \
+	-DCMAKE_NO_SYSTEM_FROM_IMPORTED=TRUE -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR
 
 if [ $? -ne 0 ]
 then
@@ -105,7 +103,7 @@ then
   exit 1
 fi
 
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "grpc make failed"
diff --git a/demos/grpc/download_and_install_openssl.sh b/demos/grpc/download_and_install_openssl.sh
index b15037e1..b139c0b8 100755
--- a/demos/grpc/download_and_install_openssl.sh
+++ b/demos/grpc/download_and_install_openssl.sh
@@ -14,7 +14,7 @@ then
   echo "./config command failed."
   exit 1
 fi
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "make command failed."
diff --git a/demos/grpc/prepare_client_server.sh b/demos/grpc/prepare_client_server.sh
index b7b209a9..38dd62c6 100755
--- a/demos/grpc/prepare_client_server.sh
+++ b/demos/grpc/prepare_client_server.sh
@@ -1,15 +1,17 @@
 #!/bin/sh
+DEMO_DIR=$PWD
 
-cd grpc/examples/cpp/helloworld
-git apply  ../../../../Makefile.patch
+cd $DEMO_DIR/grpc/examples/cpp/helloworld
+git apply $DEMO_DIR/Makefile.patch
 if [ $? -ne 0 ]
 then
   echo "patch failed"
   exit 1
 fi
-cp ../../protos/helloworld.proto .
 
-cd ../../../../
+cp $DEMO_DIR/grpc/examples/protos/helloworld.proto .
+
+cd $DEMO_DIR
 
 mkdir -p client
 mkdir -p server
diff --git a/demos/grpc/run_client_on_host.sh b/demos/grpc/run_client_on_host.sh
index 5d201404..5408cd67 100755
--- a/demos/grpc/run_client_on_host.sh
+++ b/demos/grpc/run_client_on_host.sh
@@ -1,12 +1,12 @@
 #!/bin/sh
 
-install_dir=/usr/local/occlum/x86_64-linux-musl
+INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl
 
-export PATH=$PATH:$install_dir/bin
+export PATH=$PATH:$INSTALL_DIR/bin
 
 cd client
 
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "demo make failed"
diff --git a/demos/grpc/run_client_on_occlum.sh b/demos/grpc/run_client_on_occlum.sh
index 4ea419a9..0da03743 100755
--- a/demos/grpc/run_client_on_occlum.sh
+++ b/demos/grpc/run_client_on_occlum.sh
@@ -1,11 +1,11 @@
 #!/bin/bash
-install_dir=/usr/local/occlum/x86_64-linux-musl
+INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl
 
-export PATH=$PATH:$install_dir/bin
+export PATH=$PATH:$INSTALL_DIR/bin
 
 cd client
 
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "demo make failed"
@@ -26,9 +26,9 @@ fi
 mkdir -p image/etc
 cp /etc/resolv.conf image/etc
 cp ../greeter_client image/bin
-cp $install_dir/lib/libprotobuf.so.3.10.0.0 image/lib
-cp $install_dir/lib/libcares.so.2 image/lib
-cp $install_dir/lib/libz.so.1 image/lib
+cp $INSTALL_DIR/lib/libprotobuf.so.3.10.0.0 image/lib
+cp $INSTALL_DIR/lib/libcares.so.2 image/lib
+cp $INSTALL_DIR/lib/libz.so.1 image/lib
 if [ $? -ne 0 ]
 then
   echo "libraries copied failed"
diff --git a/demos/grpc/run_server_on_host.sh b/demos/grpc/run_server_on_host.sh
index c0d37ab7..afec9151 100755
--- a/demos/grpc/run_server_on_host.sh
+++ b/demos/grpc/run_server_on_host.sh
@@ -1,12 +1,12 @@
 #!/bin/sh
 
-install_dir=/usr/local/occlum/x86_64-linux-musl
+INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl
 
-export PATH=$PATH:$install_dir/bin
+export PATH=$PATH:$INSTALL_DIR/bin
 
 cd server
 
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "demo make failed"
diff --git a/demos/grpc/run_server_on_occlum.sh b/demos/grpc/run_server_on_occlum.sh
index 0b603af0..0da98cba 100755
--- a/demos/grpc/run_server_on_occlum.sh
+++ b/demos/grpc/run_server_on_occlum.sh
@@ -1,10 +1,10 @@
 #!/bin/bash
-install_dir=/usr/local/occlum/x86_64-linux-musl
-export PATH=$PATH:$install_dir/bin
+INSTALL_DIR=/usr/local/occlum/x86_64-linux-musl
+export PATH=$PATH:$INSTALL_DIR/bin
 
 cd server
 
-make -j8
+make -j$(nproc)
 if [ $? -ne 0 ]
 then
   echo "demo make failed"
@@ -25,9 +25,9 @@ fi
 mkdir -p image/etc
 cp /etc/resolv.conf image/etc
 cp ../greeter_server image/bin
-cp $install_dir/lib/libprotobuf.so.3.10.0.0 image/lib
-cp $install_dir/lib/libcares.so.2 image/lib
-cp $install_dir/lib/libz.so.1 image/lib
+cp $INSTALL_DIR/lib/libprotobuf.so.3.10.0.0 image/lib
+cp $INSTALL_DIR/lib/libcares.so.2 image/lib
+cp $INSTALL_DIR/lib/libz.so.1 image/lib
 if [ $? -ne 0 ]
 then
   echo "libraries copied failed"
diff --git a/demos/remote_attestation/download_and_build.sh b/demos/remote_attestation/download_and_build.sh
index a0963189..5d6612d3 100755
--- a/demos/remote_attestation/download_and_build.sh
+++ b/demos/remote_attestation/download_and_build.sh
@@ -32,7 +32,7 @@ if [ ! -d "$CURLDIR" ] ; then
     mv curl-curl-7_29_0 curl && \
     echo "Download curl successfully" || exit 1
 else
-    echo "The openssl code is already existent"
+    echo "The curl code is already existent"
 fi
 
 # Download other dependencies
@@ -88,7 +88,8 @@ if [ ! -f "$INSTALLDIR/lib/libcurl.so" ] ; then
     echo "Building curl ..."
     CC=occlum-gcc CXX=occlum-g++ ./configure \
       --prefix=$INSTALLDIR \
-      --with-ssl=$INSTALLDIR && \
+      --with-ssl=$INSTALLDIR \
+      --without-zlib && \
     make -j${nproc} && \
     sudo make install && \
     echo "Build curl successfully" || exit 1