diff --git a/RESOURCES/OPTIONS/fswebcam/fswebcam.sh b/RESOURCES/OPTIONS/fswebcam/fswebcam.sh
index 4f8e230..8956cdb 100755
--- a/RESOURCES/OPTIONS/fswebcam/fswebcam.sh
+++ b/RESOURCES/OPTIONS/fswebcam/fswebcam.sh
@@ -14,19 +14,14 @@ project_root="$1"
 fswebcam_package="$2"
 
 # check the required tools
-TOOL_LIST=("unzip")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
-    fi
+TOOL_LIST="unzip"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+    exit 1
   fi
-  i=$(($i + 1))
 done
 
 # check the project root folder
diff --git a/RESOURCES/OPTIONS/opkg/opkg.sh b/RESOURCES/OPTIONS/opkg/opkg.sh
index e5b4c30..4d0a26c 100755
--- a/RESOURCES/OPTIONS/opkg/opkg.sh
+++ b/RESOURCES/OPTIONS/opkg/opkg.sh
@@ -14,19 +14,14 @@ project_root="$1"
 opkg_package="$2"
 
 # check the required tools
-TOOL_LIST=("unzip")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
-    fi
+TOOL_LIST="unzip"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+    exit 1
   fi
-  i=$(($i + 1))
 done
 
 # check the project root folder
diff --git a/RESOURCES/OPTIONS/python/python.sh b/RESOURCES/OPTIONS/python/python.sh
index 4599e7d..bd8f204 100755
--- a/RESOURCES/OPTIONS/python/python.sh
+++ b/RESOURCES/OPTIONS/python/python.sh
@@ -14,19 +14,14 @@ project_root="$1"
 python_package="$2"
 
 # check the required tools
-TOOL_LIST=("unzip")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "$project_root/TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
-    fi
+TOOL_LIST="unzip"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+    exit 1
   fi
-  i=$(($i + 1))
 done
 
 # check the project root folder
diff --git a/RESOURCES/OPTIONS/ssh/ssh.sh b/RESOURCES/OPTIONS/ssh/ssh.sh
index d242838..6e70efd 100755
--- a/RESOURCES/OPTIONS/ssh/ssh.sh
+++ b/RESOURCES/OPTIONS/ssh/ssh.sh
@@ -14,19 +14,14 @@ project_root="$1"
 ssh_package="$2"
 
 # check the required tools
-TOOL_LIST=("unzip")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
-    fi
+TOOL_LIST="unzip"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+    exit 1
   fi
-  i=$(($i + 1))
 done
 
 # check the project root folder
diff --git a/RESOURCES/OPTIONS/uart/uart.sh b/RESOURCES/OPTIONS/uart/uart.sh
index d4a665b..a49de95 100755
--- a/RESOURCES/OPTIONS/uart/uart.sh
+++ b/RESOURCES/OPTIONS/uart/uart.sh
@@ -14,19 +14,14 @@ project_root="$1"
 uart_package="$2"
 
 # check the required tools
-TOOL_LIST=("unzip")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
-    fi
+TOOL_LIST="unzip"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+    exit 1
   fi
-  i=$(($i + 1))
 done
 
 # check the project root folder
diff --git a/RESOURCES/OPTIONS/webcam/webcam.sh b/RESOURCES/OPTIONS/webcam/webcam.sh
index 5be9373..2f03d95 100755
--- a/RESOURCES/OPTIONS/webcam/webcam.sh
+++ b/RESOURCES/OPTIONS/webcam/webcam.sh
@@ -16,28 +16,24 @@ webcam_package="$2"
 # check the required tools
 app_version_tool=$(which app_version.sh)
 app_model_tool=$(which app_model.sh)
-TOOL_LIST=("unzip" "app_version.sh" "app_model.sh")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  toolname=${TOOL_LIST[$i]}
-  echo "Checking tool: $toolname"
-  tpath=$(which "$toolname")
-  if [ -z "$tpath" ]; then
-    local_tool_path="$project_root/TOOLS/$toolname"
+TOOL_LIST="unzip app_version.sh app_model.sh"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    local_tool_path="$project_root/TOOLS/$tool_name"
     if [ ! -f "$local_tool_path" ]; then
-      echo -e "${RED}ERROR: Missing tool '$toolname' ${NC}"
+      echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
       exit 2
     else
-      if [ "$toolname" == "app_version.sh" ]; then
+      if [ "$tool_name" == "app_version.sh" ]; then
         app_version_tool="$local_tool_path"
       fi
-      if [ "$toolname" == "app_model.sh" ]; then
+      if [ "$tool_name" == "app_model.sh" ]; then
         app_model_tool="$local_tool_path"
       fi
     fi
   fi
-  i=$(($i + 1))
 done
 
 # check the project root folder
@@ -95,23 +91,23 @@ if [ "$app_ver" == "3.0.9" ]; then
   sed -i 's/video4linux/videoXlinux/g' "$def_target"
   if [ "$app_model" == "K2Pro" ]; then
     # stop the app to log the message 'cannot open video'
-    printf "\x00\xf0\x20\xe3" | dd of="$def_target" bs=1 seek=2339112 conv=notrunc &>>/dev/null
+    printf "\x00\xf0\x20\xe3" | dd of="$def_target" bs=1 seek=2339112 conv=notrunc
     # slow captive portal commmunication
-    printf "\xff\x8f\x0f\xe3" | dd of="$def_target" bs=1 seek=63492 conv=notrunc &>>/dev/null
+    printf "\xff\x8f\x0f\xe3" | dd of="$def_target" bs=1 seek=63492 conv=notrunc
     exit 0
   fi
   if [ "$app_model" == "K2Plus" ]; then
     # stop the app to log the message 'cannot open video'
-    printf "\x00\xf0\x20\xe3" | dd of="$def_target" bs=1 seek=2339152 conv=notrunc &>>/dev/null
+    printf "\x00\xf0\x20\xe3" | dd of="$def_target" bs=1 seek=2339152 conv=notrunc
     # slow captive portal commmunication
-    printf "\xff\x8f\x0f\xe3" | dd of="$def_target" bs=1 seek=63492 conv=notrunc &>>/dev/null
+    printf "\xff\x8f\x0f\xe3" | dd of="$def_target" bs=1 seek=63492 conv=notrunc
     exit 0
   fi
   if [ "$app_model" == "K2Max" ]; then
     # stop the app to log the message 'cannot open video'
-    printf "\x00\xf0\x20\xe3" | dd of="$def_target" bs=1 seek=2339152 conv=notrunc &>>/dev/null
+    printf "\x00\xf0\x20\xe3" | dd of="$def_target" bs=1 seek=2339152 conv=notrunc
     # slow captive portal commmunication
-    printf "\xff\x8f\x0f\xe3" | dd of="$def_target" bs=1 seek=63492 conv=notrunc &>>/dev/null
+    printf "\xff\x8f\x0f\xe3" | dd of="$def_target" bs=1 seek=63492 conv=notrunc
     exit 0
   fi
 fi
diff --git a/fwdl.sh b/fwdl.sh
index 99f2ba0..7b77b23 100755
--- a/fwdl.sh
+++ b/fwdl.sh
@@ -22,19 +22,16 @@ if [ "$par_model" != "K2Pro" ] && [ "$par_model" != "K2Plus" ] && [ "$par_model"
 fi
 
 # check the required tools
-TOOL_LIST=("curl" "wc" "awk")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
+TOOL_LIST="curl wc awk"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    if [ ! -f "TOOLS/$tool_name" ]; then
+      echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+      exit 3
     fi
   fi
-  i=$(($i + 1))
 done
 
 url_bin="https://cdn.cloud-universe.anycubic.com/ota/${par_model}/AC104_${par_model}_1.1.0_${par_version}_update.bin"
diff --git a/pack.sh b/pack.sh
index caa0295..c3a5634 100755
--- a/pack.sh
+++ b/pack.sh
@@ -9,17 +9,14 @@ NC='\033[0m'
 FILES="sw-description sw-description.sig boot-resource uboot boot0 kernel rootfs dsp0 cpio_item_md5"
 
 # check the required tools
-TOOL_LIST=("md5sum" "openssl" "sha256sum" "mksquashfs")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
+TOOL_LIST="md5sum openssl sha256sum mksquashfs"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
     exit 1
   fi
-  i=$(($i + 1))
 done
 
 # remove the last created update
diff --git a/patch.sh b/patch.sh
index fc480a6..e89cf4c 100755
--- a/patch.sh
+++ b/patch.sh
@@ -27,19 +27,14 @@ if [ ! -f "$optionsfile" ]; then
 fi
 
 # check the required tools
-TOOL_LIST=("awk")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
-      exit 2
-    fi
+TOOL_LIST="awk"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
+    exit 1
   fi
-  i=$(($i + 1))
 done
 
 # remove the old result file for the installed options
diff --git a/unpack.sh b/unpack.sh
index 38e1311..4cc91e9 100755
--- a/unpack.sh
+++ b/unpack.sh
@@ -29,19 +29,16 @@ if [ "$UPDATE_FILE_EXT" != "bin" ] && [ "$UPDATE_FILE_EXT" != "swu" ] && [ "$UPD
 fi
 
 # check the required tools
-TOOL_LIST=("cpio" "unsquashfs" "unzip" "ack2_swu_decrypt.py" "python3")
-i=0
-part_num=${#TOOL_LIST[*]}
-while [ $i -lt $((part_num)) ]; do
-  echo "Checking tool: ${TOOL_LIST[$i]}"
-  t=$(which "${TOOL_LIST[$i]}")
-  if [ -z "$t" ]; then
-    if [ ! -f "TOOLS/${TOOL_LIST[$i]}" ]; then
-      echo -e "${RED}ERROR: Missing tool '${TOOL_LIST[$i]}' ${NC}"
+TOOL_LIST="cpio unsquashfs unzip ack2_swu_decrypt.py python3"
+for tool_name in $TOOL_LIST; do
+  echo "Checking tool: $tool_name"
+  tool_path=$(which "$tool_name")
+  if [ -z "$tool_path" ]; then
+    if [ ! -f "TOOLS/$tool_name" ]; then
+      echo -e "${RED}ERROR: Missing tool '$tool_name' ${NC}"
       exit 3
     fi
   fi
-  i=$(($i + 1))
 done
 
 # set the custom decrypt tool