diff --git a/src/answer.sh b/src/answer.sh
index 273fc199..068cb3e9 100644
--- a/src/answer.sh
+++ b/src/answer.sh
@@ -1557,49 +1557,4 @@ legacyInstall() {
   return 0
 }
 
-legacyPrepare() {
-
-  local iso="$1"
-  local dir="$2"
-  local desc="$3"
-
-  local tmp="$TMP/boot-images"
-  local image="$tmp/eltorito_img1_bios.img"
-
-  ETFS="boot.img"
-  [ -f "$dir/$ETFS" ] && [ -s "$dir/$ETFS" ] && return 0
-
-  rm -f "$dir/$ETFS" || return 1
-  rm -rf "$tmp" || return 1
-
-  LC_ALL=C xorriso \
-      -no_rc \
-      -osirrox on \
-      -indev "$iso" \
-      -extract_boot_images "$tmp" >/dev/null 2>&1 || {
-    local rc=$?
-    rm -rf "$tmp" || true
-
-    (( rc > 128 )) && exit "$rc"
-
-    error "Failed to extract boot image from $desc ISO!"
-    return 1
-  }
-
-  if [ ! -s "$image" ]; then
-    rm -rf "$tmp" || true
-    error "Failed to locate BIOS boot image in $desc ISO!"
-    return 1
-  fi
-
-  if ! mv -f "$image" "$dir/$ETFS"; then
-    rm -rf "$tmp" || true
-    error "Failed to save boot image from $desc ISO!"
-    return 1
-  fi
-
-  rm -rf "$tmp" || return 1
-  return 0
-}
-
 return 0
diff --git a/src/define.sh b/src/define.sh
index 44b401ed..7425edd0 100644
--- a/src/define.sh
+++ b/src/define.sh
@@ -11,6 +11,7 @@ set -Eeuo pipefail
 : "${EDITION:=""}"
 : "${MANUAL:=""}"
 : "${REMOVE:=""}"
+: "${REBUILD:="N"}"
 : "${VERSION:=""}"
 : "${COMMAND:=""}"
 : "${DETECTED:=""}"
diff --git a/src/image.sh b/src/image.sh
index e7f1b495..ba6527e0 100644
--- a/src/image.sh
+++ b/src/image.sh
@@ -951,3 +951,65 @@ EOF
 
   return 0
 }
+
+extractBootImage() {
+
+  local iso="$1"
+  local dir="$2"
+  local desc="$3"
+
+  local tmp="$TMP/boot-images"
+  local image="$tmp/eltorito_img1_bios.img"
+  local max_size=$((32 * 1024 * 1024))
+
+  ETFS="boot.img"
+  [ -f "$dir/$ETFS" ] && [ -s "$dir/$ETFS" ] && return 0
+
+  rm -f "$dir/$ETFS" || return 1
+  rm -rf "$tmp" || return 1
+
+  LC_ALL=C xorriso \
+      -no_rc \
+      -osirrox on \
+      -indev "$iso" \
+      -extract_boot_images "$tmp" >/dev/null 2>&1 || {
+    local rc=$?
+    rm -rf "$tmp" || true
+
+    (( rc > 128 )) && exit "$rc"
+
+    error "Failed to extract boot image from $desc ISO!"
+    return 1
+  }
+
+  if [ ! -s "$image" ]; then
+    rm -rf "$tmp" || true
+    error "Failed to locate BIOS boot image in $desc ISO!"
+    return 1
+  fi
+
+  local size
+
+  if ! size=$(stat -c%s "$image"); then
+    rm -rf "$tmp" || true
+    error "Failed to determine BIOS boot image size in $desc ISO!"
+    return 1
+  fi
+
+  if (( size > max_size )); then
+    rm -rf "$tmp" || true
+    error "The BIOS boot image in $desc ISO exceeds 32 MB!"
+    return 1
+  fi
+
+  if ! mv -f "$image" "$dir/$ETFS"; then
+    rm -rf "$tmp" || true
+    error "Failed to save boot image from $desc ISO!"
+    return 1
+  fi
+
+  rm -rf "$tmp" || return 1
+  return 0
+}
+
+return 0
diff --git a/src/install.sh b/src/install.sh
index 11290344..a08df391 100644
--- a/src/install.sh
+++ b/src/install.sh
@@ -769,26 +769,29 @@ prepareImage() {
 
   desc=$(printVariant "$DETECTED" "$DETECTED")
 
+  # Adjust QEMU machine configuration for legacy versions
   setMachine "$DETECTED" "$iso" "$dir" "$desc" || return 1
+
+  disabled "$REBUILD" && return 0
   skipVersion "$DETECTED" && return 0
 
-  if [[ "${BOOT_MODE,,}" != "windows_legacy" ]]; then
+  if [[ "${BOOT_MODE,,}" == "windows_legacy" ]]; then
 
-    [ -f "$dir/$ETFS" ] && [ -s "$dir/$ETFS" ] &&
-      [ -f "$dir/$EFISYS" ] && [ -s "$dir/$EFISYS" ] && return 0
+    extractBootImage "$iso" "$dir" "$desc" && return 0
 
-    missing=$(basename "$dir/$EFISYS")
-    if [ ! -f "$dir/$ETFS" ] || [ ! -s "$dir/$ETFS" ]; then
-      missing=$(basename "$dir/$ETFS")
-    fi
-
-    error "Failed to locate file \"${missing,,}\" in ISO image!"
+    error "Failed to extract boot image from ISO image \"${iso}\"!"
     return 1
   fi
 
-  legacyPrepare "$iso" "$dir" "$desc" && return 0
+  [ -f "$dir/$ETFS" ] && [ -s "$dir/$ETFS" ] &&
+    [ -f "$dir/$EFISYS" ] && [ -s "$dir/$EFISYS" ] && return 0
 
-  error "Failed to extract boot image from ISO image!"
+  missing=$(basename "$dir/$EFISYS")
+  if [ ! -f "$dir/$ETFS" ] || [ ! -s "$dir/$ETFS" ]; then
+    missing=$(basename "$dir/$ETFS")
+  fi
+
+  error "Failed to locate file \"${missing,,}\" in ISO image!"
   return 1
 }
 
@@ -962,6 +965,11 @@ updateImage() {
   local dat="${xml//.xml/.dat}"
   local desc path src wim name info
 
+  if disabled "$REBUILD"; then
+    info "Skipping modifications to the installation image..."
+    return 1
+  fi
+
   skipVersion "${DETECTED,,}" && return 0
 
   if [ ! -s "$asset" ] || [ ! -f "$asset" ]; then