diff --git a/reinstall.sh b/reinstall.sh
index fd126a8..82d6cbc 100644
--- a/reinstall.sh
+++ b/reinstall.sh
@@ -63,7 +63,7 @@ info() {
 }
 
 warn() {
-    echo_color_text '\e[33m' "Warn: $*"
+    echo_color_text '\e[33m' "Warning: $*"
 }
 
 error() {
@@ -230,7 +230,7 @@ test_url_real() {
         error_and_exit "$@"
     }
 
-    tmp_file=$tmp/reinstall-img-test
+    tmp_file=$tmp/img-test
 
     # 有的服务器不支持 range，curl会下载整个文件
     # 用 dd 限制下载 1M
@@ -1010,8 +1010,40 @@ setos() {
 
     # shellcheck disable=SC2154
     setos_dd() {
-        test_url $img 'xz|gzip' ${step}_img_type
+        test_url $img 'xz|gzip' img_type
+
+        if is_efi; then
+            install_pkg hexdump $img_type
+
+            # od 在 coreutils 里面，好像要配合 tr 才能删除空格
+            # hexdump 在 util-linux / bsdmainutils 里面
+            # xxd 要单独安装，el 在 vim-common 里面
+            # xxd -l $((34 * 4096)) -ps -c 512
+
+            # 仅打印前34个扇区 * 4096字节（按最大的算）
+            # 每行512字节
+            "$img_type" -dc <"$tmp/img-test" | hexdump -n $((34 * 4096)) -e '512/1 "%02x" "\n"' -v >$tmp/img-test-raw
+            if grep -q '^28732ac11ff8d211ba4b00a0c93ec93b' $tmp/img-test-raw; then
+                echo 'DD: Image is EFI.'
+            else
+                echo 'DD: Image is not EFI.'
+                warn '
+The current machine uses EFI boot, but the DD image is not an EFI image.
+Continue with DD? [Y/N]
+
+当前机器使用 EFI 引导，但 DD 镜像不是 EFI 镜像。
+继续 DD? [Y/N]
+'
+                read -r -n 1
+                if [[ "$REPLY" = [Yy] ]]; then
+                    eval ${step}_confirmed_no_efi=1
+                else
+                    exit
+                fi
+            fi
+        fi
         eval "${step}_img='$img'"
+        eval "${step}_img_type='$img_type'"
     }
 
     setos_centos_alma_rocky_fedora() {
@@ -1316,6 +1348,12 @@ install_pkg() {
             *) pkg="util-linux" ;;
             esac
             ;;
+        hexdump)
+            case "$pkg_mgr" in
+            apt) pkg="bsdmainutils" ;;
+            *) pkg="util-linux" ;;
+            esac
+            ;;
         unsquashfs)
             case "$pkg_mgr" in
             zypper) pkg="squashfs" ;;
diff --git a/trans.sh b/trans.sh
index f1e47fa..fa6a8e9 100644
--- a/trans.sh
+++ b/trans.sh
@@ -633,7 +633,13 @@ add_fallback_efi_to_nvram() {
             efibootmgr --bootorder "$new_order"
         fi
     else
-        echo "
+        # shellcheck disable=SC2154
+        if [ "$confirmed_no_efi" = 1 ]; then
+            echo 'Confirmed no EFI in previous step.'
+        else
+            # reinstall.sh 里确认过一遍，但是逻辑扇区大于 512 时，可能漏报？
+            # 这里的应该会根据逻辑扇区来判断？
+            echo "
 Warning: This machine is currently using EFI boot, but the main hard drive does not have an EFI partition.
 If this machine supports Legacy BIOS boot (CSM), you can safely restart into the new system by running the reboot command.
 If this machine does not support Legacy BIOS boot (CSM), you will not be able to enter the new system after rebooting.
@@ -642,7 +648,8 @@ If this machine does not support Legacy BIOS boot (CSM), you will not be able to
 如果本机支持 Legacy BIOS 引导 (CSM)，你可以运行 reboot 命令安全地重启到新系统。
 如果本机不支持 Legacy BIOS 引导 (CSM)，重启后将无法进入新系统。
 "
-        exit
+            exit
+        fi
     fi
 }