diff --git a/README.en.md b/README.en.md
index abe9a60..f3ba360 100644
--- a/README.en.md
+++ b/README.en.md
@@ -16,7 +16,7 @@ One-Click Script to Reinstall System [中文](README.md)
 ## Highlights
 
 - One-click Linux installation: Supports 19 common distributions.
-- One-click Windows installation: Uses the official ISO for installation instead of custom images. The script automatically retrieves the ISO link and installs `Virtio` and other drivers.
+- One-click Windows installation: Uses the official ISO for installation instead of custom images. The script can automatically ~~retrieves the ISO link~~ and installs common drivers like `Virtio`.
 - Supports installation in any direction, i.e., `Linux to Linux`, `Linux to Windows`, `Windows to Windows`, `Windows to Linux`
 - No need to input IP parameters; automatically recognizes dynamic and static IPs, supports `/32`, `/128`, `gateway outside subnet`, `IPv6 only`, `dual NIC` and other special network configurations
 - Specially optimized for low-spec servers, requires less memory than the official netboot
diff --git a/README.md b/README.md
index 463349a..3524b66 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@
 ## 亮点
 
 - 一键安装 Linux，支持 19 种常见发行版
-- 一键安装 Windows，使用官方 ISO 安装而非自制镜像，脚本会自动获取 ISO 链接、自动安装 Virtio 等驱动
+- 一键安装 Windows，使用官方 ISO 安装而非自制镜像，~~脚本会自动获取 ISO 链接~~、自动安装 Virtio 等常见驱动
 - 支持任意方向重装，即 `Linux to Linux`、`Linux to Windows`、`Windows to Windows`、`Windows to Linux`
 - 无需填写 IP 参数，自动识别动静态，支持 `/32`、`/128`、`网关不在子网范围内`、`纯 IPv6`、`双网卡` 等特殊网络
 - 专门适配低配小鸡，比官方 netboot 需要更少的内存
diff --git a/reinstall.bat b/reinstall.bat
index ae11a41..af00357 100644
--- a/reinstall.bat
+++ b/reinstall.bat
@@ -6,8 +6,8 @@ set confhome=https://raw.githubusercontent.com/bin456789/reinstall/main
 set confhome_cn=https://gitlab.com/bin456789/reinstall/-/raw/main
 rem set confhome_cn=https://www.ghproxy.cc/https://raw.githubusercontent.com/bin456789/reinstall/main
 
-set pkgs=curl,cpio,p7zip,ipcalc,dos2unix,jq,xz,gzip,zstd,openssl,bind-utils,libiconv,binutils
-set cmds=curl,cpio,p7zip,ipcalc,dos2unix,jq,xz,gzip,zstd,openssl,nslookup,iconv,ar
+set pkgs=curl,cpio,p7zip,dos2unix,jq,xz,gzip,zstd,openssl,bind-utils,libiconv,binutils
+set cmds=curl,cpio,p7zip,dos2unix,jq,xz,gzip,zstd,openssl,nslookup,iconv,ar
 
 rem 65001 代码页会乱码
 
@@ -202,7 +202,6 @@ exit /b 1
 set "cmds_space=%cmds:,= %"
 for %%c in (%cmds_space%) do (
     if not exist "%SystemDrive%\cygwin\bin\%%c" if not exist "%SystemDrive%\cygwin\bin\%%c.exe" (
-        echo %%c not found.
         exit /b 1
     )
 )
diff --git a/reinstall.sh b/reinstall.sh
index 9ba8194..9abe261 100644
--- a/reinstall.sh
+++ b/reinstall.sh
@@ -126,11 +126,24 @@ curl() {
     done
 }
 
+mask2cidr() {
+    local x=${1##*255.}
+    set -- 0^^^128^192^224^240^248^252^254^ $(((${#1} - ${#x}) * 2)) ${x%%.*}
+    x=${1%%"$3"*}
+    echo $(($2 + (${#x} / 4)))
+}
+
 is_in_china() {
     [ "$force_cn" = 1 ] && return 0
 
     if [ -z "$_loc" ]; then
         # www.cloudflare.com/dash.cloudflare.com 国内访问的是美国服务器，而且部分地区被墙
+        # 备用 www.bose.cn
+        # 备用 www.qualcomm.cn
+        # 备用 www.prologis.cn
+        # 备用 www.garmin.com.cn
+        # 备用 www.autodesk.com.cn
+        # 备用 www.keysight.com.cn
         _loc=$(curl -L http://www.visa.cn/cdn-cgi/trace | grep '^loc=' | cut -d= -f2)
         if [ -z "$_loc" ]; then
             error_and_exit "Can not get location."
@@ -1475,7 +1488,7 @@ Continue with DD?
             fi
         done
 
-        iso=$(curl -L https://fnnas.com | grep -o 'https://[^"]*\.iso' | head -1)
+        iso=$(curl -L https://fnnas.com/ | grep -o 'https://[^"]*\.iso' | head -1)
         test_url "$iso" 'iso'
         eval "${step}_iso='$iso'"
     }
@@ -2380,7 +2393,9 @@ collect_netconf() {
                         ip=${ips[i]}
                         subnet=${subnets[i]}
                         if [[ "$ip" = *.* ]]; then
-                            cidr=$(ipcalc -b "$ip/$subnet" | grep Netmask: | awk '{print $NF}')
+                            # ipcalc 依赖 perl，会使 cygwin 增加 ~50M
+                            # cidr=$(ipcalc -b "$ip/$subnet" | grep Netmask: | awk '{print $NF}')
+                            cidr=$(mask2cidr "$subnet")
                             ipv4_addr="$ip/$cidr"
                             ipv4_gateway="$gateway"
                             ipv4_mac="$mac_addr"