diff --git a/prebuilds/usr/sbin/download_pkg b/prebuilds/usr/sbin/download_pkg
index af47846..65402e6 100755
--- a/prebuilds/usr/sbin/download_pkg
+++ b/prebuilds/usr/sbin/download_pkg
@@ -4,6 +4,14 @@
 # shell 执行参数，分别为 -e(命令执行错误则退出脚本) -u(变量未定义则报错) -x(打印实际待执行的命令行)
 set -eux
 
+# 定义错误处理函数，添加错误位置信息
+error() {
+    local error_location="$1"
+    local error_message="$2"
+    echo "Error at $error_location: $error_message" >&2
+    exit 1
+}
+
 print_usage() {
   echo "Usage: download_pkg <COMMAND> <PACKAGE-NAME> \"<URLS>\" [OPTIONS]"
   echo ""
@@ -35,41 +43,44 @@ check_pgp() {
     local name_asc=${1:?missing asc file name}
     local name=${2:?missing file name}
     local keys="${3:?missing key id}"
-	
+    
     GNUPGHOME="$(mktemp -d)"
-	if which gpg >/dev/null 2>&1; then
-		for key in $keys; do
-        gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys "${key}" || 
-        gpg --batch --keyserver pgp.mit.edu --recv-keys "${key}" || 
-        gpg --batch --keyserver keys.gnupg.net --recv-keys "${key}" || 
-        gpg --batch --keyserver keyserver.pgp.com --recv-keys "${key}"; 
-	    done
-	    gpg --batch --verify "$name_asc" "$name"
-	    command -v gpgconf > /dev/null && gpgconf --kill all
-	fi
+    if which gpg >/dev/null 2>&1; then
+        local key_servers=("pgp.mit.edu" "keys.gnupg.net" "keyserver.pgp.com" "ha.pool.sks-keyservers.net")
+        for key in $keys; do
+            for server in "${key_servers[@]}"; do
+                if gpg --batch --keyserver "$server" --recv-keys "${key}" --timeout 10; then
+                    break
+                fi
+            done
+        done
+        gpg --batch --verify "$name_asc" "$name" || error "PGP verification" "PGP verification failed"
+        command -v gpgconf > /dev/null && gpgconf --kill all
+    fi
 }
 
 # 获取并解析参数 
-ARGS=$(getopt -o g:s:h -l "checkpgp:,checksum:,help" -n "download-pkg" -- "$@")
-if [ $? -ne 0 ];
-then
-  exit 1
+parsed_args=$(getopt -o g:s:h -l "checkpgp:,checksum:,help" -n "download-pkg" -- "$@")
+if [ $? -ne 0 ]; then
+    error "Parameter parsing" "Failed to parse command line arguments."
+    print_usage
+    exit 1
 fi
 
-eval set -- "$ARGS";
+eval set -- "$parsed_args";
 while true; do
   case "$1" in
     -g|--checkpgp)
       shift
       if [ -n "$1" ]; then
-        PACKAGE_KEYS=$1
+        package_keys=$1
         shift
       fi
       ;;
     -s|--checksum)
       shift
       if [ -n "$1" ]; then
-        PACKAGE_SHA256=$1
+        package_sha256=$1
         shift
       fi
       ;;
@@ -88,7 +99,7 @@ done
 case "$1" in
   download|install|unpack) ;;
   *)
-    error "Unrecognized command: $1"
+    error "Command validation" "Unrecognized command: $1"
     print_usage
     exit 1
     ;;
@@ -96,40 +107,50 @@ esac
 
 # 检测输入参数是否足够，需要至少提供软件包名称 及 下载路径
 if [ $# -lt 3 ]; then
+  error "Parameter validation" "Insufficient parameters. Please provide package name and URLs."
   print_usage
   exit 1
 fi
 
-INSTALL_ROOT=/usr/local
-CACHE_ROOT=/tmp
+install_root=/usr/local
+cache_root=/tmp
 
-PACKAGE="$2"
-PACKAGE_URLS=$3
+package="$2"
+package_urls=$3
 
-cd $INSTALL_ROOT
-
-echo "Downloading $PACKAGE package"
-for url in $PACKAGE_URLS; do
-  echo "Try $url/$PACKAGE"
-    if wget -O "$CACHE_ROOT/$PACKAGE" "$url/$PACKAGE" && [ -s "$CACHE_ROOT/$PACKAGE" ]; then
-      if [ -n "${PACKAGE_KEYS:-}" ]; then
-        wget -O "$CACHE_ROOT/$PACKAGE.asc" "$url/$PACKAGE.asc" || wget -O "$CACHE_ROOT/$PACKAGE.asc" "$url/$PACKAGE.sign" || :
-        if [ ! -e "$CACHE_ROOT/$PACKAGE.asc" ]; then
-          exit 1
+# 检查缓存目录中是否已存在该软件包
+if [ -e "$cache_root/$package" ]; then
+    echo "Package already exists in cache: $cache_root/$package"
+else
+    cd $install_root
+    echo "Downloading $package package"
+    for url in $package_urls; do
+      echo "Try $url/$package"
+        if wget -T 10 -O "$cache_root/$package" "$url/$package" && [ -s "$cache_root/$package" ]; then
+          if [ -n "${package_keys:-}" ]; then
+            wget -T 10 -O "$cache_root/$package.asc" "$url/$package.asc" || wget -T 10 -O "$cache_root/$package.asc" "$url/$package.sign" || :
+            if [ ! -e "$cache_root/$package.asc" ]; then
+              error "PGP signature download" "Failed to download PGP signature file."
+              exit 1
+            fi
+          fi
+          break
+        else
+            echo "Failed to download from $url/$package"
         fi
-      fi
-      break
-    fi
-done
-
-if [ -n "${PACKAGE_SHA256:-}" ]; then
-	echo "Verifying package integrity"
-	echo "$PACKAGE_SHA256 *$CACHE_ROOT/$PACKAGE" | sha256sum -c -
+    done
 fi
 
-if [ -e "$CACHE_ROOT/$PACKAGE.asc" ]; then
-	echo "Verifying package with PGP"
-  check_pgp "$CACHE_ROOT/$PACKAGE.asc" "$CACHE_ROOT/$PACKAGE" "$PACKAGE_KEYS"
+if [ -n "${package_sha256:-}" ]; then
+    echo "Verifying package integrity"
+    if ! echo "$package_sha256 *$cache_root/$package" | sha256sum -c -; then
+        error "SHA256 verification" "SHA256 verification failed"
+    fi
+fi
+
+if [ -e "$cache_root/$package.asc" ]; then
+    echo "Verifying package with PGP"
+    check_pgp "$cache_root/$package.asc" "$cache_root/$package" "$package_keys"
 fi
 
 # If the tarball has too many files, it can trigger a bug
@@ -137,27 +158,26 @@ fi
 # to workaround it. As the overhead is too big (~40 MB), it is not added by
 # default. Source: https://github.com/coreos/bugs/issues/1095
 
-
 # 安装或解压软件
 case "$1" in
-	download)
-		echo "Download success: $CACHE_ROOT/$PACKAGE"
-		;;
-	install) 
-		echo "Installing $PACKAGE"
-		cp $CACHE_ROOT/$PACKAGE /usr/local/sbin/
-		;;
-	unpack) 
-		if ! tar -taf $CACHE_ROOT/$PACKAGE >/dev/null 2>&1; then
-			echo "Invalid or corrupt '$PACKAGE' package."
-			exit 1
-		fi
-		echo "Unpacking $PACKAGE to $CACHE_ROOT" 
-    cd $CACHE_ROOT
-		if which bsdtar >/dev/null 2>&1; then
-  		bsdtar -xf $CACHE_ROOT/$PACKAGE
-		else
-      tar --no-same-owner -xaf $CACHE_ROOT/$PACKAGE
-		fi
-		;;
+    download)
+        echo "Download success: $cache_root/$package"
+        ;;
+    install) 
+        echo "Installing $package"
+        cp $cache_root/$package /usr/local/sbin/
+        ;;
+    unpack) 
+        if ! tar -taf $cache_root/$package >/dev/null 2>&1; then
+            error "Package integrity check" "Invalid or corrupt '$package' package."
+            exit 1
+        fi
+        echo "Unpacking $package to $cache_root" 
+        cd $cache_root
+        if which bsdtar >/dev/null 2>&1; then
+            bsdtar -xf $cache_root/$package
+        else
+            tar --no-same-owner -xaf $cache_root/$package
+        fi
+        ;;
 esac
diff --git a/prebuilds/usr/sbin/install_pkg b/prebuilds/usr/sbin/install_pkg
index f29f099..a1c6b48 100755
--- a/prebuilds/usr/sbin/install_pkg
+++ b/prebuilds/usr/sbin/install_pkg
@@ -1,9 +1,15 @@
 #!/bin/bash
-# Ver: 1.0 by Endial Fang (endial@126.com)
+# Ver: 1.2 by Endial Fang (endial@126.com)
 # 
 # shell 执行参数，分别为 -e(命令执行错误则退出脚本) -u(变量未定义则报错) -x(打印实际待执行的命令行)
 set -eux
 
+# 检查用户权限
+if [ "$EUID" -ne 0 ]; then
+    echo "Error: This script must be run as root."
+    exit 1
+fi
+
 print_usage() {
   echo "Usage: install_pkg <PACKAGE-NAME>"
   echo ""
@@ -23,36 +29,43 @@ if [ $# -lt 1 ]; then
   exit 1
 fi
 
-case "$1" in
-  -h|--help)
-    print_usage
-    exit 0
-    ;;
-esac
+# 解析命令行参数
+UPDATE=true
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        -h|--help)
+            print_usage
+            exit 0
+            ;;
+        *)
+            break
+            ;;
+    esac
+done
 
 retry=0
 max=2
+export DEBIAN_FRONTEND=noninteractive && 
+
 until [ $retry -gt $max ]; do
-  set +e
-  (
-    export DEBIAN_FRONTEND=noninteractive &&
-    apt-get update &&
-    apt-get upgrade -y &&
-    apt-get install -y --no-install-recommends "$@"
-  )
-  CODE=$?
-  set -e
-  if [ $CODE -eq 0 ]; then
-    break
-  fi
-  if [ $retry -eq $max ]; then
-    exit $CODE
-  fi
-  echo "apt failed, retrying"
-  retry=$(($retry + 1))
+    set +e
+    (
+        apt-get update &&
+        apt-get install -y --no-install-recommends $*
+    )
+    CODE=$?
+    set -e
+    if [ $CODE -eq 0 ]; then
+        break
+    fi
+    if [ $retry -eq $max ]; then
+        echo "Failed to install packages after $max retries."
+        exit $CODE
+    fi
+    echo "apt failed, retrying"
+    retry=$(($retry + 1))
 done
 
-apt-get purge -y --auto-remove
-apt-get autoclean -y
-
+apt-get purge -y --auto-remove && apt-get autoclean -y || :
 rm -rf /var/lib/apt/lists /var/cache/apt/archives || :
+echo "Installation completed successfully."
diff --git a/prebuilds/usr/sbin/select_source b/prebuilds/usr/sbin/select_source
index 3fe07f8..448aa20 100755
--- a/prebuilds/usr/sbin/select_source
+++ b/prebuilds/usr/sbin/select_source
@@ -1,7 +1,31 @@
 #!/bin/bash
-# Ver: 1.0 by Endial Fang (endial@126.com)
+# Ver: 1.2 by Endial Fang (endial@126.com)
 # 
+# 此脚本用于根据传入的参数选择对应的 apt 源配置文件并复制到指定目录
 # shell 执行参数，分别为 -e(命令执行错误则退出脚本) -u(变量未定义则报错) -x(打印实际待执行的命令行)
 set -eux
 
-cp /etc/apt/sources/${1:-default}.sources /etc/apt/sources.list.d/debian.sources
+# 检查是否有足够的权限
+if [ "$EUID" -ne 0 ]; then
+    echo "Error: This script must be run as root."
+    exit 1
+fi
+
+# 获取用户传入的参数，若未传入则使用默认值 "default"
+source_name=${1:-default}
+
+# 定义源文件路径
+source_file="/etc/apt/sources/${source_name}.sources"
+
+# 检查源文件是否存在
+if [ ! -f "$source_file" ]; then
+    echo "Error: Source file $source_file does not exist."
+    exit 1
+fi
+
+# 定义目标文件路径
+target_file="/etc/apt/sources.list.d/debian.sources"
+
+# 复制源文件到目标文件
+cp "$source_file" "$target_file"
+echo "Successfully selected apt source: $source_name"