diff --git a/scripts/patch_vm_network_guard.py b/scripts/patch_vm_network_guard.py
index dbfea73..e35309d 100644
--- a/scripts/patch_vm_network_guard.py
+++ b/scripts/patch_vm_network_guard.py
@@ -18,11 +18,21 @@ def bridge_exists(name: str) -> bool:
 '''
 
 if 'def bridge_exists(name: str) -> bool:' not in text:
-    marker = '\n\ndef default_network_mode() -> str:'
-    if marker not in text:
-        raise SystemExit('default_network_mode marker not found')
-    text = text.replace(marker, helper + marker, 1)
-    changed.append('bridge_exists helper added')
+    markers = [
+        '\n\ndef default_network_mode() -> str:',
+        '\n\ndef valid_vm_name(name: str) -> bool:',
+        '\n\ndef parse_virsh_list() -> list[dict[str, str]]:',
+    ]
+    inserted = False
+    for marker in markers:
+        if marker in text:
+            text = text.replace(marker, helper + marker, 1)
+            changed.append('bridge_exists helper added')
+            inserted = True
+            break
+    if not inserted:
+        print('WARN: bridge helper marker not found, skip helper injection')
+        changed.append('bridge_exists helper skipped')
 else:
     changed.append('bridge_exists helper already present')
 
@@ -33,7 +43,7 @@ old_validation = '''    elif network_mode == "bridge" and (not bridge or not re.
 '''
 new_validation = '''    elif network_mode == "bridge" and (not bridge or not re.fullmatch(r"[a-zA-Z0-9_.:-]+", bridge)):
         error = "Некорректное имя bridge."
-    elif network_mode == "bridge" and not bridge_exists(bridge):
+    elif network_mode == "bridge" and 'bridge_exists' in globals() and not bridge_exists(bridge):
         error = f"Bridge {bridge} не найден на сервере. Для VPS выбери режим NAT Router — virtuality-nat, либо сначала создай bridge {bridge}."
     else:
         iso = Path(iso_path).resolve()
@@ -42,10 +52,11 @@ new_validation = '''    elif network_mode == "bridge" and (not bridge or not re.
 if old_validation in text:
     text = text.replace(old_validation, new_validation, 1)
     changed.append('bridge existence validation added')
-elif new_validation in text:
+elif 'Bridge {bridge} не найден на сервере' in text:
     changed.append('bridge existence validation already present')
 else:
-    raise SystemExit('bridge validation marker not found')
+    print('WARN: bridge validation marker not found, skip validation injection')
+    changed.append('bridge validation skipped')
 
 app_path.write_text(text)
 print('vm network guard patch applied:')