diff --git a/src/omni_pca/mock_panel.py b/src/omni_pca/mock_panel.py
index 9c9313a..4de942c 100644
--- a/src/omni_pca/mock_panel.py
+++ b/src/omni_pca/mock_panel.py
@@ -52,7 +52,7 @@ import secrets
 from collections.abc import AsyncIterator, Callable
 from contextlib import asynccontextmanager
 from dataclasses import dataclass, field
-from typing import ClassVar
+from typing import Any, ClassVar
 
 from .commands import Command
 from .crypto import (
@@ -266,6 +266,52 @@ class MockState:
         self.thermostats = _promote_dict(self.thermostats, MockThermostatState)
         self.buttons = _promote_dict(self.buttons, MockButtonState)
 
+    @classmethod
+    def from_pca(
+        cls,
+        path_or_bytes: str | bytes,
+        key: int,
+        **overrides: Any,
+    ) -> MockState:
+        """Build a MockState seeded from a real .pca file.
+
+        Populated from the .pca:
+
+        * ``model_byte`` + ``firmware_*`` — drive SystemInformation replies
+          so a connected client sees the panel the .pca came from.
+        * ``programs`` — every non-empty Program record from the 1500-slot
+          table, encoded back to wire bytes so UploadProgram / UploadPrograms
+          serve them exactly as a real panel would.
+
+        Everything else uses MockState defaults (or whatever the caller
+        passes as ``**overrides``). Per-object name/state tables aren't
+        in the .pca header that pca_file currently extracts, so zones /
+        units / areas / thermostats default to empty unless the caller
+        explicitly provides them.
+
+        ``key=0`` only works for files where the export keystream was
+        already applied (e.g., the result of ``decrypt_pca_bytes`` with
+        the same key); use ``KEY_EXPORT`` (391549495) for unmodified
+        PC Access exports.
+        """
+        from .pca_file import parse_pca_file
+
+        acct = parse_pca_file(path_or_bytes, key=key)
+        programs = {
+            p.slot: p.encode_wire_bytes()
+            for p in acct.programs
+            if p.slot is not None and not p.is_empty()
+        }
+        defaults: dict[str, Any] = {
+            "model_byte": acct.model,
+            "firmware_major": acct.firmware_major,
+            "firmware_minor": acct.firmware_minor,
+            "firmware_revision": acct.firmware_revision,
+            "programs": programs,
+        }
+        defaults.update(overrides)
+        return cls(**defaults)
+
     # ---- name-bytes helpers (kept for back-compat with old callers) -----
 
     def zone_name_bytes(self, idx: int) -> bytes:
diff --git a/tests/test_e2e_program_echo.py b/tests/test_e2e_program_echo.py
index ca09680..b5ff52f 100644
--- a/tests/test_e2e_program_echo.py
+++ b/tests/test_e2e_program_echo.py
@@ -314,6 +314,48 @@ async def test_v2_client_iter_programs_empty_state_yields_nothing() -> None:
 # ---- v1 client iter_programs (high-level wrapper over iter_streaming) ----
 
 
+@pytest.mark.asyncio
+async def test_mockstate_from_pca_serves_real_panel_programs() -> None:
+    """End-to-end: build MockState from the live .pca, drive iter_programs
+    over v2 wire, decode every yielded Program. This exercises the full
+    file → mock → wire → decoder pipeline with real on-disk data.
+
+    The fixture is the same plain-text dump tests/test_pca_file.py uses;
+    we re-encrypt with KEY_EXPORT on the fly so parse_pca_file accepts it.
+    """
+    from pathlib import Path
+
+    from omni_pca.client import OmniClient
+    from omni_pca.mock_panel import MockState
+    from omni_pca.pca_file import KEY_EXPORT, decrypt_pca_bytes
+
+    plain = Path("/home/kdm/home-auto/HAI/pca-re/extracted/Our_House.pca.plain")
+    if not plain.is_file():
+        pytest.skip(f"live fixture missing: {plain}")
+    encrypted = decrypt_pca_bytes(plain.read_bytes(), KEY_EXPORT)
+
+    state = MockState.from_pca(encrypted, key=KEY_EXPORT)
+    # SystemInfo fields were populated from the .pca header.
+    assert state.model_byte == 16          # OMNI_PRO_II
+    assert state.firmware_major == 2
+    # Programs: 330 defined per Phase 1 recon.
+    assert len(state.programs) == 330
+
+    panel = MockPanel(controller_key=CONTROLLER_KEY, state=state)
+    async with panel.serve(transport="tcp") as (host, port):
+        async with OmniClient(
+            host=host, port=port, controller_key=CONTROLLER_KEY, timeout=2.0
+        ) as c:
+            decoded = [p async for p in c.iter_programs()]
+
+    # Every defined slot streamed back, in ascending slot order.
+    assert len(decoded) == 330
+    assert [p.slot for p in decoded] == sorted(state.programs)
+    # Spot check: every decoded record has a known ProgramType.
+    for p in decoded:
+        assert p.prog_type in {1, 2, 3}  # TIMED / EVENT / YEARLY from this fixture
+
+
 @pytest.mark.asyncio
 async def test_v1_client_iter_programs_enumerates_all_seeded() -> None:
     seeded = {