@@ -45,6 +45,7 @@
 )
 from .data.enums import InverterType
 from .data.solis_config import CONNECTION_METHOD, SOLIS_INVERTERS, InverterConfig, inverter_options_from_config
+from .helpers import hmi_version_supports_v2
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -270,7 +271,7 @@ async def async_step_cloud(self, user_input=None):
             if self._both_mode:
                 # The dual entry is keyed by the Modbus serial; the cloud plant must contain it
                 user_input = {**user_input, CONF_INVERTER_SERIAL: self._modbus_data[CONF_INVERTER_SERIAL]}
-            serial, inverter_id, detected_model, product_model, error = await self._validate_cloud_config(user_input)
+            serial, inverter_id, detected_model, product_model, detected_has_v2, error = await self._validate_cloud_config(user_input)
             if error:
                 errors["base"] = error
             elif self._both_mode:
@@ -282,6 +283,14 @@ async def async_step_cloud(self, user_input=None):
                         serial,
                     )
                     self._modbus_data["model"] = detected_model
+                if detected_has_v2 is not None and self._modbus_data.get("has_v2") != detected_has_v2:
+                    _LOGGER.info(
+                        "HMI firmware version identifies TOU V2 support=%s; overriding has_v2=%s for serial %s",
+                        detected_has_v2,
+                        self._modbus_data.get("has_v2"),
+                        serial,
+                    )
+                    self._modbus_data["has_v2"] = detected_has_v2
                 self._cloud_data = user_input
                 self._resolved_serial = serial
                 self._resolved_cloud_id = inverter_id
@@ -298,9 +307,17 @@ async def async_step_cloud(self, user_input=None):
                         user_input.get("model"),
                         serial,
                     )
+                if detected_has_v2 is not None and user_input.get("has_v2") != detected_has_v2:
+                    _LOGGER.info(
+                        "HMI firmware version identifies TOU V2 support=%s; overriding has_v2=%s for serial %s",
+                        detected_has_v2,
+                        user_input.get("has_v2"),
+                        serial,
+                    )
                 data = {
                     **user_input,
                     "model": detected_model or user_input.get("model"),
+                    "has_v2": detected_has_v2 if detected_has_v2 is not None else user_input.get("has_v2"),
                     CONF_INVERTER_SERIAL: serial,
                     CONF_CLOUD_INVERTER_ID: inverter_id,
                     CONF_CLOUD_PRODUCT_MODEL: product_model,
@@ -361,10 +378,10 @@ async def async_step_dual_mode(self, user_input=None):
             data_schema=vol.Schema({vol.Required("dual_mode", default="failover_modbus"): vol.In(DUAL_MODE_OPTIONS)}),
         )
 
-    async def _validate_cloud_config(self, user_input) -> tuple[str | None, str | None, str | None, str | None, str | None]:
+    async def _validate_cloud_config(self, user_input) -> tuple[str | None, str | None, str | None, str | None, bool | None, str | None]:
         """Check credentials against the SolisCloud API and resolve the inverter serial + cloud id.
 
-        Returns (serial, inverter_id, detected_model, product_model, None) on success.
+        Returns (serial, inverter_id, detected_model, product_model, detected_has_v2, None) on success.
         The cloud id is required alongside the serial for inverterDetail reads.
         """
         from homeassistant.helpers.aiohttp_client import async_get_clientsession
@@ -384,26 +401,36 @@ async def _validate_cloud_config(self, user_input) -> tuple[str | None, str | No
             records = await client.async_inverter_list(user_input[CONF_CLOUD_PLANT_ID].strip())
         except SolisCloudApiError as error:
             _LOGGER.warning("SolisCloud validation failed: %s", error)
-            return None, None, None, None, "Cannot reach the SolisCloud API with these credentials. Check the key id/secret and plant id."
+            return None, None, None, None, None, "Cannot reach the SolisCloud API with these credentials. Check the key id/secret and plant id."
 
         by_serial = {str(rec["sn"]).upper(): rec for rec in records if rec.get("sn")}
         if not by_serial:
-            return None, None, None, None, "No inverters found for this plant id."
+            return None, None, None, None, None, "No inverters found for this plant id."
+
+        async def _resolve(serial: str, record: dict):
+            metadata = cloud_model_metadata(record)
+            product_model = metadata.get("productModel") or metadata.get("model")
+            inverter_id = str(record.get("id") or "") or None
+            detected_has_v2 = None
+            # inverterList doesn't include hmiVersionAll; that field is only in inverterDetail
+            # (the same call cloud_retrieval.py already makes every poll cycle).
+            try:
+                detail = await client.async_inverter_detail(serial, inverter_id)
+            except SolisCloudApiError as error:
+                _LOGGER.debug("HMI version lookup failed for serial %s during setup: %s", serial, error)
+            else:
+                detected_has_v2 = hmi_version_supports_v2(detail.get("hmiVersionAll"))
+            return serial, inverter_id, infer_model_from_cloud_record(record), product_model, detected_has_v2, None
 
         wanted = (user_input.get(CONF_INVERTER_SERIAL) or "").strip().upper()
         if wanted:
             if wanted not in by_serial:
-                return None, None, None, None, f"Inverter serial {wanted} not found in this plant (found: {', '.join(by_serial)})."
-            record = by_serial[wanted]
-            metadata = cloud_model_metadata(record)
-            product_model = metadata.get("productModel") or metadata.get("model")
-            return wanted, str(record.get("id") or "") or None, infer_model_from_cloud_record(record), product_model, None
+                return None, None, None, None, None, f"Inverter serial {wanted} not found in this plant (found: {', '.join(by_serial)})."
+            return await _resolve(wanted, by_serial[wanted])
         if len(by_serial) == 1:
             serial, record = next(iter(by_serial.items()))
-            metadata = cloud_model_metadata(record)
-            product_model = metadata.get("productModel") or metadata.get("model")
-            return serial, str(record.get("id") or "") or None, infer_model_from_cloud_record(record), product_model, None
-        return None, None, None, None, f"This plant has multiple inverters ({', '.join(by_serial)}); please enter the serial of the one to add."
+            return await _resolve(serial, record)
+        return None, None, None, None, None, f"This plant has multiple inverters ({', '.join(by_serial)}); please enter the serial of the one to add."
 
     async def async_step_reconfigure(self, user_input=None):
         """Handle reconfiguration."""
@@ -451,7 +478,7 @@ async def async_step_reconfigure_cloud(self, user_input=None):
         entry = self.hass.config_entries.async_get_entry(self.context["entry_id"])
 
         if user_input is not None:
-            serial, inverter_id, detected_model, product_model, error = await self._validate_cloud_config(user_input)
+            serial, inverter_id, detected_model, product_model, detected_has_v2, error = await self._validate_cloud_config(user_input)
             if error:
                 errors["base"] = error
             elif serial != entry.unique_id:
@@ -464,10 +491,18 @@ async def async_step_reconfigure_cloud(self, user_input=None):
                         user_input.get("model"),
                         serial,
                     )
+                if detected_has_v2 is not None and user_input.get("has_v2") != detected_has_v2:
+                    _LOGGER.info(
+                        "HMI firmware version identifies TOU V2 support=%s; overriding has_v2=%s for serial %s",
+                        detected_has_v2,
+                        user_input.get("has_v2"),
+                        serial,
+                    )
                 data = {
                     **entry.data,
                     **user_input,
                     "model": detected_model or user_input.get("model"),
+                    "has_v2": detected_has_v2 if detected_has_v2 is not None else user_input.get("has_v2"),
                     CONF_INVERTER_SERIAL: serial,
                     CONF_CLOUD_INVERTER_ID: inverter_id,
                     CONF_CLOUD_PRODUCT_MODEL: product_model,
@@ -561,6 +596,26 @@ async def _validate_config(self, user_input):
                 else:
                     await modbus_controller.async_read_input_register(35000, 1)
 
+                # Auto-detect TOU V2 support from HMI firmware version (register 33002) rather
+                # than relying solely on the form's manual toggle. A failed/unparseable read
+                # must never block setup; the user's chosen value survives untouched.
+                try:
+                    hmi_registers = await modbus_controller.async_read_input_register(33002, 1)
+                except Exception as hmi_error:
+                    _LOGGER.debug("HMI version read failed during setup; leaving has_v2 as configured: %s", hmi_error)
+                else:
+                    if hmi_registers:
+                        detected_has_v2 = hmi_version_supports_v2(hmi_registers[0])
+                        if detected_has_v2 is not None and user_input.get("has_v2") != detected_has_v2:
+                            _LOGGER.info(
+                                "HMI version %s identifies TOU V2 support=%s; overriding has_v2=%s for serial %s",
+                                hmi_registers[0],
+                                detected_has_v2,
+                                user_input.get("has_v2"),
+                                user_input.get(CONF_INVERTER_SERIAL),
+                            )
+                            user_input["has_v2"] = detected_has_v2
+
                 return True, None
             except Exception as e:
                 _LOGGER.warning(f"Connection failed attempt {attempt + 1}/5: {str(e)}")
 
@@ -159,6 +159,29 @@ def decode_inverter_model(hex_value):
     return protocol_version, model_description
 
 
+# HMI firmware version at or above this value supports TOU V2 (Grid Time of Use). Verified
+# live: an inverter reporting hmiVersionAll/register 33002 = "4B00" is confirmed running V2,
+# so 0x4B00 is the boundary-inclusive minimum, not an earlier (wrong) 0xFB00 guess.
+V2_HMI_VERSION_THRESHOLD = 0x4B00
+
+
+def hmi_version_supports_v2(raw: int | str | None) -> bool | None:
+    """Whether an HMI firmware version indicates TOU V2 support.
+
+    Accepts either the raw Modbus register integer (register 33002) or the SolisCloud
+    hex string (`inverterDetail` field `hmiVersionAll`, e.g. "4B00") — both encode the
+    same raw value. Returns None if undeterminable rather than raising, so callers can
+    fall back to whatever the user already configured.
+    """
+    if raw is None:
+        return None
+    try:
+        value = int(raw, 16) if isinstance(raw, str) else int(raw)
+    except (TypeError, ValueError):
+        return None
+    return value >= V2_HMI_VERSION_THRESHOLD
+
+
 def controller_scope(controller) -> str:
     """Protocol-neutral scope shared by all controllers talking to one inverter.
 
 
@@ -2,6 +2,8 @@
 
 Solis hybrid inverters expose two independent, non-interacting sets of scheduled charge/discharge controls. SolisConnect maps both, but they cover different register ranges, different slot counts, and different levels of Modbus/SolisCloud parity.
 
+The config flow's "V2 support" toggle is auto-detected from the inverter's HMI firmware version (Modbus register `33002`, or SolisCloud `inverterDetail` field `hmiVersionAll`) whenever that read succeeds: an HMI version at or above `0x4B00` supports V2. Detection silently overrides whatever the installer picked in the form (same pattern as automatic model detection); if the read fails or is unparseable, the form's choice is left as-is rather than blocking setup.
+
 ## Summary
 
 | | Time-Charging (V1) | Grid Time of Use V2 |
 
@@ -248,9 +248,15 @@ async def test_migration_v3_to_v4_sets_modbus_only(hass: HomeAssistant):
 
 
 async def test_config_flow_cloud_branch_creates_entry(hass: HomeAssistant):
-    with patch(
-        "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
-        new=AsyncMock(return_value=[{"id": "1", "sn": "sn999", "productModel": "3102"}]),
+    with (
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
+            new=AsyncMock(return_value=[{"id": "1", "sn": "sn999", "productModel": "3102"}]),
+        ),
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_detail",
+            new=AsyncMock(return_value={"hmiVersionAll": "4B00"}),
+        ),
     ):
         result = await hass.config_entries.flow.async_init(DOMAIN, context={"source": "user"})
         assert result["type"] == "form" and result["step_id"] == "user"
@@ -277,6 +283,7 @@ async def test_config_flow_cloud_branch_creates_entry(hass: HomeAssistant):
         assert result["data"]["model"] == "S5-EH1P"
         assert result["data"][CONF_PROTOCOL_MODE] == PROTO_CLOUD_ONLY
         assert result["title"] == "Solis: SN999 (Cloud)"
+        assert result["data"]["has_v2"] is True  # hmiVersionAll "4B00" meets the V2 threshold
 
 
 async def test_config_flow_cloud_bad_credentials_shows_error(hass: HomeAssistant):
@@ -302,9 +309,15 @@ async def test_reconfigure_cloud_entry_uses_cloud_form(hass: HomeAssistant):
     entry = _cloud_entry()
     entry.add_to_hass(hass)
 
-    with patch(
-        "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
-        new=AsyncMock(return_value=[{"id": "CLOUDID1", "sn": SERIAL}]),
+    with (
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
+            new=AsyncMock(return_value=[{"id": "CLOUDID1", "sn": SERIAL}]),
+        ),
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_detail",
+            new=AsyncMock(return_value={}),
+        ),
     ):
         result = await entry.start_reconfigure_flow(hass)
         assert result["type"] == "form"
@@ -329,10 +342,52 @@ async def test_reconfigure_cloud_entry_uses_cloud_form(hass: HomeAssistant):
         assert entry.data[CONF_CLOUD_INVERTER_ID] == "CLOUDID1"
 
 
+async def test_reconfigure_cloud_entry_hmi_version_overrides_has_v2(hass: HomeAssistant):
+    """Issue #20: reconfiguring a cloud-only entry also picks up HMI-based V2 detection."""
+    entry = _cloud_entry()
+    entry.add_to_hass(hass)
+
+    with (
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
+            new=AsyncMock(return_value=[{"id": "CLOUDID1", "sn": SERIAL}]),
+        ),
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_detail",
+            new=AsyncMock(return_value={"hmiVersionAll": "4B00"}),
+        ),
+    ):
+        result = await entry.start_reconfigure_flow(hass)
+
+        with (
+            patch("custom_components.solisconnect.async_setup_entry", return_value=True),
+            patch("custom_components.solisconnect.async_unload_entry", return_value=True),
+        ):
+            result = await hass.config_entries.flow.async_configure(
+                result["flow_id"],
+                {
+                    CONF_CLOUD_KEY_ID: "kid2",
+                    CONF_CLOUD_KEY_SECRET: "ksecret2",
+                    CONF_CLOUD_PLANT_ID: "plant1",
+                    CONF_INVERTER_SERIAL: SERIAL,
+                    "model": "S6-EH1P",
+                    "has_v2": False,  # form choice; the detected "4B00" should override it
+                },
+            )
+        assert result["type"] == "abort" and result["reason"] == "reconfigure_successful"
+        assert entry.data["has_v2"] is True
+
+
 async def test_config_flow_cloud_multiple_inverters_requires_serial(hass: HomeAssistant):
-    with patch(
-        "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
-        new=AsyncMock(return_value=[{"id": "1", "sn": "SNA"}, {"id": "2", "sn": "SNB"}]),
+    with (
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
+            new=AsyncMock(return_value=[{"id": "1", "sn": "SNA"}, {"id": "2", "sn": "SNB"}]),
+        ),
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_detail",
+            new=AsyncMock(return_value={}),
+        ),
     ):
         result = await hass.config_entries.flow.async_init(DOMAIN, context={"source": "user"})
         result = await hass.config_entries.flow.async_configure(result["flow_id"], {CONF_CONNECTION_TYPE: CONN_TYPE_CLOUD})
@@ -370,6 +425,10 @@ async def test_dual_flow_cloud_model_overrides_wrong_modbus_model(hass: HomeAssi
             "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_list",
             new=AsyncMock(return_value=[{"id": "1", "sn": "sn999", "productModel": "3102"}]),
         ),
+        patch(
+            "custom_components.solisconnect.cloud.api_client.SolisCloudApiClient.async_inverter_detail",
+            new=AsyncMock(return_value={}),
+        ),
     ):
         result = await hass.config_entries.flow.async_init(DOMAIN, context={"source": "user"})
         result = await hass.config_entries.flow.async_configure(result["flow_id"], {CONF_CONNECTION_TYPE: CONN_TYPE_BOTH})
@@ -405,3 +464,6 @@ async def test_dual_flow_cloud_model_overrides_wrong_modbus_model(hass: HomeAssi
         assert result["data"]["model"] == "S5-EH1P"
         assert result["data"][CONF_CLOUD_DETECTED_MODEL] == "S5-EH1P"
         assert result["data"][CONF_PROTOCOL_MODE] == PROTO_BOTH_FAILOVER
+        # HMI read (register 33002) returned [1] via the blanket async_read_input_register
+        # patch, well below the V2 threshold -> overrides the user's has_v2=True to False.
+        assert result["data"]["has_v2"] is False