[Fix] X1C Virtual Printer not accepting sends (#735)

X1C and X1 virtual printers used legacy SSDP model codes
  (3DPrinter-X1-Carbon, 3DPrinter-X1) that BambuStudio doesn't
  recognize, causing "incompatible printer preset" errors when
  sending prints. Changed to the correct codes (BL-P001, BL-P002)
  that real printers report via SSDP.

  Also fixed proxy mode auto-inherit storing printer display names
  (e.g. "X1C") instead of SSDP codes, by adding a resolution layer
  that maps display names to model codes.

  DB migration auto-converts existing VPs on startup.

backend/app/api/routes/virtual_printers.py

@@ -40,6 +40,23 @@ class VirtualPrinterUpdate(BaseModel):
     remote_interface_ip: str | None = None
 
 
+def _resolve_printer_model(printer_model: str | None) -> str | None:
+    """Map a printer's model (display name or SSDP code) to a valid VP SSDP model code.
+
+    Printers store display names like 'X1C' while VPs need SSDP codes like 'BL-P001'.
+    """
+    if not printer_model:
+        return None
+    from backend.app.services.virtual_printer import VIRTUAL_PRINTER_MODELS
+    from backend.app.services.virtual_printer.manager import DISPLAY_NAME_TO_MODEL_CODE
+
+    # Already a valid SSDP model code
+    if printer_model in VIRTUAL_PRINTER_MODELS:
+        return printer_model
+    # Map display name to SSDP code
+    return DISPLAY_NAME_TO_MODEL_CODE.get(printer_model)
+
+
 def _vp_to_dict(vp, status: dict | None = None) -> dict:
     """Convert VirtualPrinter model to response dict."""
     from backend.app.services.virtual_printer import VIRTUAL_PRINTER_MODELS
@@ -172,7 +189,7 @@ async def create_virtual_printer(
         enabled=body.enabled,
         mode=body.mode,
         model=body.model
-        or (target_printer.model if target_printer and target_printer.model and body.mode == "proxy" else None)
+        or _resolve_printer_model(target_printer.model if target_printer and body.mode == "proxy" else None)
         or DEFAULT_VIRTUAL_PRINTER_MODEL,
         access_code=body.access_code,
         target_printer_id=body.target_printer_id,
@@ -276,7 +293,7 @@ async def update_virtual_printer(
         vp.target_printer_id = body.target_printer_id
         # Auto-inherit model from target printer in proxy mode (unless user explicitly set model)
         if body.model is None and vp.mode == "proxy" and target_printer.model:
-            vp.model = target_printer.model
+            vp.model = _resolve_printer_model(target_printer.model) or target_printer.model
     if body.auto_dispatch is not None:
         vp.auto_dispatch = body.auto_dispatch
     if body.bind_ip is not None:
@@ -291,7 +308,7 @@ async def update_virtual_printer(
         result = await db.execute(select(PrinterModel).where(PrinterModel.id == vp.target_printer_id))
         existing_target = result.scalar_one_or_none()
         if existing_target and existing_target.model:
-            vp.model = existing_target.model
+            vp.model = _resolve_printer_model(existing_target.model) or existing_target.model
 
     # Determine final enabled state
     explicitly_enabling = body.enabled is True

backend/app/core/database.py

@@ -1321,7 +1321,7 @@ async def run_migrations(conn):
 
                 result = await conn.execute(text("SELECT value FROM settings WHERE key = 'virtual_printer_model'"))
                 row = result.fetchone()
-                old_model = row[0] if row else "3DPrinter-X1-Carbon"
+                old_model = row[0] if row else "BL-P001"
 
                 result = await conn.execute(
                     text("SELECT value FROM settings WHERE key = 'virtual_printer_target_printer_id'")
@@ -1440,6 +1440,33 @@ async def run_migrations(conn):
     except OperationalError:
         pass  # Already applied
 
+    # Migration: Fix VP model codes — convert legacy SSDP codes and display names to correct SSDP codes
+    # Legacy codes (from multi-VP refactor) and display names (from proxy auto-inherit)
+    vp_model_fixes = {
+        "3DPrinter-X1-Carbon": "BL-P001",
+        "3DPrinter-X1": "BL-P002",
+        "X1C": "BL-P001",
+        "X1": "BL-P002",
+        "X1E": "C13",
+        "P1P": "C11",
+        "P1S": "C12",
+        "P2S": "N7",
+        "A1": "N2S",
+        "A1 Mini": "N1",
+        "H2D": "O1D",
+        "H2C": "O1C",
+        "H2S": "O1S",
+    }
+    for old_val, new_val in vp_model_fixes.items():
+        await conn.execute(
+            text("UPDATE virtual_printers SET model = :new WHERE model = :old"),
+            {"old": old_val, "new": new_val},
+        )
+        await conn.execute(
+            text("UPDATE settings SET value = :new WHERE key = 'virtual_printer_model' AND value = :old"),
+            {"old": old_val, "new": new_val},
+        )
+
     # Migration: Add per-user Bambu Cloud credential columns
     try:
         await conn.execute(text("ALTER TABLE users ADD COLUMN cloud_token VARCHAR(500)"))

backend/app/services/virtual_printer/manager.py

@@ -28,8 +28,8 @@ logger = logging.getLogger(__name__)
 #   - https://github.com/psychoticbeef/BambuLabOrcaSlicerDiscovery
 VIRTUAL_PRINTER_MODELS = {
     # X1 Series
-    "3DPrinter-X1-Carbon": "X1C",  # X1 Carbon
-    "3DPrinter-X1": "X1",  # X1
+    "BL-P001": "X1C",  # X1 Carbon
+    "BL-P002": "X1",  # X1
     "C13": "X1E",  # X1E
     # P Series
     "C11": "P1P",  # P1P
@@ -56,8 +56,8 @@ VIRTUAL_PRINTER_MODELS = {
 #   UUUUU = Unit number (5 chars)
 MODEL_SERIAL_PREFIXES = {
     # X1 Series
-    "3DPrinter-X1-Carbon": "00M00A",  # X1C
-    "3DPrinter-X1": "00M00A",  # X1
+    "BL-P001": "00M00A",  # X1C
+    "BL-P002": "00M00A",  # X1
     "C13": "03W00A",  # X1E
     # P Series
     "C11": "01S00A",  # P1P
@@ -73,8 +73,11 @@ MODEL_SERIAL_PREFIXES = {
     "O1S": "09400A",  # H2S
 }
 
+# Reverse mapping: display name → SSDP model code (for auto-inheriting from printer model)
+DISPLAY_NAME_TO_MODEL_CODE = {v: k for k, v in VIRTUAL_PRINTER_MODELS.items()}
+
 # Default model
-DEFAULT_VIRTUAL_PRINTER_MODEL = "3DPrinter-X1-Carbon"  # X1C
+DEFAULT_VIRTUAL_PRINTER_MODEL = "BL-P001"  # X1C
 
 
 def _get_serial_for_model(model: str, serial_suffix: str) -> str:

backend/app/services/virtual_printer/mqtt_server.py

@@ -18,8 +18,8 @@ MQTT_PORT = 8883
 
 # Model code → product_name for version response (must match what slicer expects)
 MODEL_PRODUCT_NAMES = {
-    "3DPrinter-X1-Carbon": "X1 Carbon",
-    "3DPrinter-X1": "X1",
+    "BL-P001": "X1 Carbon",
+    "BL-P002": "X1",
     "C13": "X1E",
     "C11": "P1P",
     "C12": "P1S",

backend/tests/unit/services/test_virtual_printer.py

@@ -54,7 +54,7 @@ class TestVirtualPrinterInstance:
             vp_id=2,
             name="X1C",
             mode="immediate",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             access_code="12345678",
             serial_suffix="391800002",
             base_dir=tmp_path,
@@ -1305,7 +1305,7 @@ class TestVirtualPrinterInstanceIPOverride:
             vp_id=20,
             name="IPTest",
             mode="immediate",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             access_code="12345678",
             serial_suffix="391800020",
             bind_ip="192.168.1.50",
@@ -1342,7 +1342,7 @@ class TestVirtualPrinterInstanceIPOverride:
             vp_id=21,
             name="NoRemote",
             mode="immediate",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             access_code="12345678",
             serial_suffix="391800021",
             bind_ip="192.168.1.50",
@@ -1368,7 +1368,7 @@ class TestVirtualPrinterInstanceIPOverride:
             vp_id=22,
             name="NoIPs",
             mode="immediate",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             access_code="12345678",
             serial_suffix="391800022",
             base_dir=tmp_path,
@@ -1396,7 +1396,7 @@ class TestBindServer:
 
         return BindServer(
             serial="01S00C000000001",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             name="Bambuddy",
         )
 
@@ -1464,7 +1464,7 @@ class TestBindServer:
     def test_bind_server_stores_config(self, bind_server):
         """Verify config is stored correctly."""
         assert bind_server.serial == "01S00C000000001"
-        assert bind_server.model == "3DPrinter-X1-Carbon"
+        assert bind_server.model == "BL-P001"
         assert bind_server.name == "Bambuddy"
         assert bind_server.version == "01.00.00.00"
 
@@ -1474,7 +1474,7 @@ class TestBindServer:
 
         server = BindServer(
             serial="01S00C000000001",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             name="Bambuddy",
             version="01.09.00.10",
         )
@@ -1501,7 +1501,7 @@ class TestBindServer:
             vp_id=99,
             name="Bambuddy",
             mode="immediate",
-            model="3DPrinter-X1-Carbon",
+            model="BL-P001",
             access_code="12345678",
             serial_suffix="391800099",
             bind_ip="192.168.1.50",
@@ -1524,9 +1524,46 @@ class TestBindServer:
 
             mock_bind_cls.assert_called_once_with(
                 serial=inst.serial,
-                model="3DPrinter-X1-Carbon",
+                model="BL-P001",
                 name="Bambuddy",
                 bind_address="192.168.1.50",
                 cert_path=Path("/tmp/cert.pem"),  # nosec B108
                 key_path=Path("/tmp/key.pem"),  # nosec B108
             )
+
+
+class TestResolveModelCodes:
+    """Tests for model code resolution (display name → SSDP code)."""
+
+    def test_display_name_to_model_code_maps_all_models(self):
+        """Verify reverse mapping covers all VIRTUAL_PRINTER_MODELS entries."""
+        from backend.app.services.virtual_printer.manager import DISPLAY_NAME_TO_MODEL_CODE, VIRTUAL_PRINTER_MODELS
+
+        for _code, display_name in VIRTUAL_PRINTER_MODELS.items():
+            assert display_name in DISPLAY_NAME_TO_MODEL_CODE
+            # For non-duplicate display names, should map back to a valid code
+            assert DISPLAY_NAME_TO_MODEL_CODE[display_name] in VIRTUAL_PRINTER_MODELS
+
+    def test_resolve_printer_model_with_ssdp_code(self):
+        """SSDP codes pass through unchanged."""
+        from backend.app.api.routes.virtual_printers import _resolve_printer_model
+
+        assert _resolve_printer_model("BL-P001") == "BL-P001"
+        assert _resolve_printer_model("O1D") == "O1D"
+        assert _resolve_printer_model("N2S") == "N2S"
+
+    def test_resolve_printer_model_with_display_name(self):
+        """Display names resolve to SSDP codes."""
+        from backend.app.api.routes.virtual_printers import _resolve_printer_model
+
+        assert _resolve_printer_model("X1C") == "BL-P001"
+        assert _resolve_printer_model("H2D") == "O1D"
+        assert _resolve_printer_model("A1") == "N2S"
+        assert _resolve_printer_model("P1S") == "C12"
+
+    def test_resolve_printer_model_with_none_or_unknown(self):
+        """None and unknown values return None."""
+        from backend.app.api.routes.virtual_printers import _resolve_printer_model
+
+        assert _resolve_printer_model(None) is None
+        assert _resolve_printer_model("UnknownModel") is None

frontend/src/__tests__/components/VirtualPrinterCard.test.tsx

@@ -30,7 +30,7 @@ vi.mock('../../api/client', () => ({
 import { multiVirtualPrinterApi } from '../../api/client';
 
 const models: Record<string, string> = {
-  '3DPrinter-X1-Carbon': 'X1C',
+  'BL-P001': 'X1C',
   'C12': 'P1S',
 };
 
@@ -39,7 +39,7 @@ const createMockPrinter = (overrides: Partial<VirtualPrinterConfig> = {}): Virtu
   name: 'Test VP',
   enabled: false,
   mode: 'immediate',
-  model: '3DPrinter-X1-Carbon',
+  model: 'BL-P001',
   model_name: 'X1C',
   access_code_set: false,
   serial: '00M00A391800001',

frontend/src/__tests__/components/VirtualPrinterSettings.test.tsx

@@ -27,7 +27,7 @@ vi.mock('../../api/client', () => ({
     updateSettings: vi.fn(),
     getModels: vi.fn().mockResolvedValue({
       models: {
-        '3DPrinter-X1-Carbon': 'X1C',
+        'BL-P001': 'X1C',
         'C12': 'P1S',
         'N7': 'P2S',
       },
@@ -43,7 +43,7 @@ const createMockSettings = (overrides = {}) => ({
   enabled: false,
   access_code_set: false,
   mode: 'immediate' as const,
-  model: '3DPrinter-X1-Carbon',
+  model: 'BL-P001',
   target_printer_id: null as number | null,
   remote_interface_ip: null as string | null,
   status: {
@@ -52,7 +52,7 @@ const createMockSettings = (overrides = {}) => ({
     mode: 'immediate',
     name: 'Bambuddy',
     serial: '00M00A391800001',
-    model: '3DPrinter-X1-Carbon',
+    model: 'BL-P001',
     model_name: 'X1C',
     pending_files: 0,
   },
@@ -158,7 +158,7 @@ describe('VirtualPrinterSettings', () => {
             mode: 'immediate',
             name: 'Bambuddy',
             serial: '00M00A391800001',
-            model: '3DPrinter-X1-Carbon',
+            model: 'BL-P001',
             model_name: 'X1C',
             pending_files: 0,
           },
@@ -512,7 +512,7 @@ describe('VirtualPrinterSettings', () => {
             mode: 'proxy',
             name: 'Bambuddy (Proxy)',
             serial: '00M00A391800001',
-            model: '3DPrinter-X1-Carbon',
+            model: 'BL-P001',
             model_name: 'X1C',
             pending_files: 0,
             proxy: {

frontend/src/components/VirtualPrinterSettings.tsx

@@ -17,7 +17,7 @@ export function VirtualPrinterSettings() {
   const [localEnabled, setLocalEnabled] = useState(false);
   const [localAccessCode, setLocalAccessCode] = useState('');
   const [localMode, setLocalMode] = useState<LocalMode>('immediate');
-  const [localModel, setLocalModel] = useState('3DPrinter-X1-Carbon');
+  const [localModel, setLocalModel] = useState('BL-P001');
   const [localTargetPrinterId, setLocalTargetPrinterId] = useState<number | null>(null);
   const [localRemoteInterfaceIp, setLocalRemoteInterfaceIp] = useState('');
   const [showAccessCode, setShowAccessCode] = useState(false);