diff --git a/test/merge_debian_isos b/test/merge_debian_isos
index c7b96604..83508d39 100755
--- a/test/merge_debian_isos
+++ b/test/merge_debian_isos
@@ -24,7 +24,8 @@ usage() {
   echo 'for which the user takes full and dangerous responsibility.' >&2
   echo 'Special result_iso path "xorriso-dd-target-plug-test" determines' >&2
   echo "on Linux the target USB stick by a dialog around plugging it in." >&2
-  echo "xorriso will be run under sudo, if xorriso-dd-target agrees." >&2
+  echo "xorriso will be run under sudo, if xorriso-dd-target agrees and" >&2
+  echo 'the user confirms by input "yes".' >&2
   echo >&2
   echo "At least the parent directory of mount_template must already exist." >&2
   echo "All arguments must be single words without using quotation marks." >&2
@@ -64,18 +65,22 @@ usage() {
   echo "  rmdir merge_mount" >&2
   echo >&2
   echo "Example writing to optical drive /dev/sr0 :" >&2
+  echo "  mkdir merge_mount" >&2
   echo "  $(basename "$0") mmc:/dev/sr0 merge_mount/iso "'\' >&2
   echo "                    debian-11.2.0-amd64-DVD-[12345].iso" >&2
+  echo "  rmdir merge_mount" >&2
   echo >&2
   echo \
   "Example on Linux writing to USB stick with xorriso-dd-target-plug-test:" >&2
   echo "  wget https://dev.lovelyhq.com/libburnia/libisoburn/raw/master/xorriso-dd-target/xorriso-dd-target" >&2
   echo "  chmod u+x xorriso-dd-target" >&2
   echo '  export XORRISO_DD_TARGET_PATH="$(pwd)"' >&2
+  echo "  mkdir merge_mount" >&2
   echo "  $(basename "$0") xorriso-dd-target-plug-test merge_mount/iso "'\' >&2
   echo "                    debian-11.2.0-amd64-DVD-[12345].iso" >&2
   echo "This leads to the first two steps of the xorriso-dd-target device" >&2
   echo "plug dialog. See: https://wiki.debian.org/XorrisoDdTarget" >&2
+  echo "  rmdir merge_mount" >&2
 }
 
 check_single_word() {
@@ -113,6 +118,38 @@ check_single_word() {
   return 0
 }
 
+XORRISO_DD_TARGET=xorriso-dd-target
+XORRISO_STDIO_DEV=
+XORRISO_SUDO=
+XORRISO_BLANK_CMD=
+XORRISO_STDIO_SYNC=off
+
+confirm_xdt_device() {
+  # $1 : path of the device file in question
+
+  echo "$XORRISO_DD_TARGET agrees that this is a suitable device." >&2
+  echo >&2
+  echo \
+     "If you agree to xorriso running under sudo and overwriting the content" \
+       >&2
+  echo "of '${1}', then enter 'yes' :" >&2
+  answer=
+  read answer
+  if test "$answer" = yes
+  then
+    XORRISO_STDIO_DEV=stdio:
+    XORRISO_SUDO=sudo
+    XORRISO_BLANK_CMD="-blank as_needed"
+    XORRISO_STDIO_SYNC=16m
+    xorriso_rm_result_iso=0
+    echo "Will use sudo with xorriso and write to device." >&2
+    return 0
+  else
+    echo "--- Answer was not 'yes'. Will not write to device." >&2
+  fi
+  return 1
+}
+
 MOUNT_LIST=
 UMOUNT_LIST=
 RMDIR_LIST=
@@ -317,7 +354,6 @@ then
   exit 5
 fi
 
-XORRISO_DD_TARGET=
 if test -z "$XORRISO_DD_TARGET_PATH"
 then
   XORRISO_DD_TARGET=xorriso-dd-target
@@ -353,15 +389,10 @@ trap cleanup_for_exit EXIT
 
 RESULT_ISO="$1"
 check_single_word "$1" "result_iso" || cleanup_and_end 1
-XORRISO_STDIO_DEV=
-XORRISO_SUDO=
-XORRISO_BLANK_CMD=
-XORRISO_STDIO_SYNC=off
 xorriso_rm_result_iso=1
 if test "$RESULT_ISO" = xorriso-dd-target-plug-test
 then
   # Get device name from xorriso-dd-target
-  advice=NO
   echo >&2
   echo \
     'Special result_iso path "xorriso-dd-target-plug-test" causes a run of' >&2
@@ -370,7 +401,9 @@ then
   echo "---------------------------------------------------------" >&2
   plugged="$("$XORRISO_DD_TARGET" -with_sudo -plug_test)"
   ret=$?
+  echo "$plugged" >&2
   echo "---------------------------------------------------------" >&2
+  advice=NO
   if test "$ret" = 0 && test -n "$plugged"
   then
     name="$(echo "$plugged" | awk '{print $1}')"
@@ -378,13 +411,14 @@ then
   fi
   if test "$advice" = YES
   then
-    RESULT_ISO=/dev/"$name"
-    XORRISO_STDIO_DEV=stdio:
-    XORRISO_SUDO=sudo
-    XORRISO_BLANK_CMD="-blank as_needed"
-    XORRISO_STDIO_SYNC=16m
-    xorriso_rm_result_iso=0
-    echo "Will use sudo with xorriso and write to ${RESULT_ISO}" >&2
+    if confirm_xdt_device /dev/"$name"
+    then
+      xorriso_rm_result_iso=0
+      RESULT_ISO=/dev/"$name"
+      echo "Actual target device path is '${RESULT_ISO}'" >&2
+    else
+      cleanup_and_end 1
+    fi
   else
     echo "--- No suitable device was determined." >&2
     cleanup_and_end 1
@@ -432,6 +466,7 @@ then
     echo \
   "Will try to overwrite the device content without sudo or pseudo-blanking." \
         >&2
+    XORRISO_STDIO_SYNC=16m
   else
     echo "--- Answer was not 'yes'. Will not write to device." >&2
     cleanup_and_end 1
@@ -454,33 +489,23 @@ then
       echo "---------------------------------------------------------" >&2
       if test "$ret" = 0
       then
-        echo "$XORRISO_DD_TARGET agrees that this is a suitable device." >&2
-        echo \
-     "If you agree to xorriso running under sudo and overwriting the content" \
-             >&2
-        echo "of '${RESULT_ISO}', then enter 'yes' :" >&2
-        answer=
-        read answer
-        if test "$answer" = yes
+        if confirm_xdt_device "$RESULT_ISO"
         then
-          XORRISO_STDIO_DEV=stdio:
-          XORRISO_SUDO=sudo
-          XORRISO_BLANK_CMD="-blank as_needed"
-          XORRISO_STDIO_SYNC=16m
-          xorriso_rm_result_iso=0
-          echo "Will use sudo with xorriso and write to device." >&2
+          dummy=dummy
         else
-          echo "--- Answer was not 'yes'. Will not write to device." >&2
+          cleanup_and_end 1
         fi
       else
         echo \
        "--- $XORRISO_DD_TARGET refuses to accept this device as result_iso" >&2
+        cleanup_and_end 1
       fi
     else
       echo "--- Helper program $XORRISO_DD_TARGET is missing." >&2
       echo \
       "--- Cannot evaluate suitability of '${RESULT_ISO}' as result_iso path" \
            >&2
+      cleanup_and_end 1
     fi
   fi
   if test -z "$XORRISO_STDIO_DEV"
diff --git a/test/merge_debian_isos.sig b/test/merge_debian_isos.sig
index 39eec19e..824fa7a5 100644
Binary files a/test/merge_debian_isos.sig and b/test/merge_debian_isos.sig differ