diff --git a/packaging/windows/drivers/pf-vdisplay/build.rs b/packaging/windows/drivers/pf-vdisplay/build.rs
index bc7bdd4..e2ae2cc 100644
--- a/packaging/windows/drivers/pf-vdisplay/build.rs
+++ b/packaging/windows/drivers/pf-vdisplay/build.rs
@@ -4,6 +4,12 @@
 fn main() -> Result<(), wdk_build::ConfigError> {
     wdk_build::configure_wdk_binary_build()?;
     link_iddcx_stub();
+    // wdk-build emits `/OPT:REF,ICF`. ICF (Identical COMDAT Folding) merges functions with identical
+    // bodies into ONE address — our many identical stub IddCx callbacks (`return STATUS_SUCCESS`) collapse
+    // to the same pointer (and even CRT EH handlers fold, hence the dumpbin `__CxxFrameHandler4 = DllMain`
+    // alias). The working virtual-display-rs links with NO `/OPT`, and IddCxAdapterInitAsync rejects a
+    // config whose distinct callbacks alias each other. Disable ICF (REF stays on); last `/OPT` wins.
+    println!("cargo::rustc-cdylib-link-arg=/OPT:NOICF");
     Ok(())
 }
 
diff --git a/packaging/windows/drivers/pf-vdisplay/src/adapter.rs b/packaging/windows/drivers/pf-vdisplay/src/adapter.rs
index ab8e853..4e4b162 100644
--- a/packaging/windows/drivers/pf-vdisplay/src/adapter.rs
+++ b/packaging/windows/drivers/pf-vdisplay/src/adapter.rs
@@ -148,6 +148,18 @@ pub fn init_adapter(device: WDFDEVICE) -> NTSTATUS {
     attr.SynchronizationScope =
         wdk_sys::_WDF_SYNCHRONIZATION_SCOPE::WdfSynchronizationScopeInheritFromParent;
     attr.ContextTypeInfo = &ADAPTER_CTX.0;
+    dbglog!(
+        "[pf-vd] rt: dev={:#x} pCaps={:#x} model={:#x} mfg={:#x} fwVer={:#x} hwVer={:#x} verSizeOf={} verSet={} diagSet={}",
+        device as usize,
+        (&raw const caps) as usize,
+        caps.EndPointDiagnostics.pEndPointModelName as usize,
+        caps.EndPointDiagnostics.pEndPointManufacturerName as usize,
+        caps.EndPointDiagnostics.pFirmwareVersion as usize,
+        caps.EndPointDiagnostics.pHardwareVersion as usize,
+        core::mem::size_of::<iddcx::IDDCX_ENDPOINT_VERSION>(),
+        version.Size,
+        caps.EndPointDiagnostics.Size,
+    );
     let init = iddcx::IDARG_IN_ADAPTER_INIT {
         WdfDevice: device,
         pCaps: &raw mut caps,
diff --git a/packaging/windows/drivers/pf-vdisplay/src/entry.rs b/packaging/windows/drivers/pf-vdisplay/src/entry.rs
index 9a7a3f3..fe3620f 100644
--- a/packaging/windows/drivers/pf-vdisplay/src/entry.rs
+++ b/packaging/windows/drivers/pf-vdisplay/src/entry.rs
@@ -12,6 +12,26 @@ use wdk_sys::{
 
 use crate::{callbacks, size, STATUS_NOT_FOUND};
 
+/// A WDF device context, attached to the WDFDEVICE at WdfDeviceCreate. The working virtual-display-rs +
+/// oracle both create the device with a context-typed `DeviceContext` (we previously passed
+/// WDF_NO_OBJECT_ATTRIBUTES). `WDF_OBJECT_CONTEXT_TYPE_INFO` holds raw pointers (Sync wrapper for the
+/// `static`); `UniqueType` self-references per `WDF_DECLARE_CONTEXT_TYPE`.
+#[repr(C)]
+struct DeviceContext {
+    _device: WDFDEVICE,
+}
+#[repr(transparent)]
+struct DevCtxInfo(wdk_sys::WDF_OBJECT_CONTEXT_TYPE_INFO);
+// SAFETY: immutable 'static type metadata; the inner raw pointers are 'static and never written.
+unsafe impl Sync for DevCtxInfo {}
+static DEVICE_CTX: DevCtxInfo = DevCtxInfo(wdk_sys::WDF_OBJECT_CONTEXT_TYPE_INFO {
+    Size: core::mem::size_of::<wdk_sys::WDF_OBJECT_CONTEXT_TYPE_INFO>() as u32,
+    ContextName: c"PfVdDeviceCtx".as_ptr().cast(),
+    ContextSize: core::mem::size_of::<DeviceContext>(),
+    UniqueType: &DEVICE_CTX.0,
+    EvtDriverGetUniqueContextType: None,
+});
+
 #[unsafe(export_name = "DriverEntry")]
 pub unsafe extern "system" fn driver_entry(
     driver: PDRIVER_OBJECT,
@@ -78,14 +98,16 @@ extern "C" fn driver_add(_driver: WDFDRIVER, mut init: PWDFDEVICE_INIT) -> NTSTA
     }
 
     let mut device: WDFDEVICE = core::ptr::null_mut();
-    // SAFETY: init configured above; no context attributes yet (STEP 3 adds DeviceContext + cleanup).
+    // Attach a device context type (like the working virtual-display-rs/oracle), not WDF_NO_OBJECT_ATTRIBUTES.
+    let mut dev_attr: wdk_sys::WDF_OBJECT_ATTRIBUTES = unsafe { core::mem::zeroed() };
+    dev_attr.Size = core::mem::size_of::<wdk_sys::WDF_OBJECT_ATTRIBUTES>() as u32;
+    dev_attr.ExecutionLevel = wdk_sys::_WDF_EXECUTION_LEVEL::WdfExecutionLevelInheritFromParent;
+    dev_attr.SynchronizationScope =
+        wdk_sys::_WDF_SYNCHRONIZATION_SCOPE::WdfSynchronizationScopeInheritFromParent;
+    dev_attr.ContextTypeInfo = &DEVICE_CTX.0;
+    // SAFETY: init configured above; dev_attr is a valid context-typed attributes block.
     let status = unsafe {
-        call_unsafe_wdf_function_binding!(
-            WdfDeviceCreate,
-            &mut init,
-            WDF_NO_OBJECT_ATTRIBUTES,
-            &mut device
-        )
+        call_unsafe_wdf_function_binding!(WdfDeviceCreate, &mut init, &mut dev_attr, &mut device)
     };
     dbglog!("[pf-vd] WdfDeviceCreate -> {status:#x}");
     if !nt_success(status) {
@@ -95,31 +117,14 @@ extern "C" fn driver_add(_driver: WDFDRIVER, mut init: PWDFDEVICE_INIT) -> NTSTA
     // IddCx must be initialized on the device BEFORE other device setup (the canonical IddCx sample order).
     // We previously created the device interface first — which can leave IddCx not fully ready by D0Entry,
     // making IddCxAdapterInitAsync reject (INVALID_PARAMETER) despite byte-perfect caps.
+    // DIAGNOSTIC (STEP 3): the WdfDeviceCreateDeviceInterface call is REMOVED. Upstream virtual-display-rs
+    // and the MS IddCx sample create NO device interface — IddCx's control channel is EvtIddCxDeviceIoControl
+    // (already registered in the config). A non-IddCx device interface registered on the IddCx/IndirectKmd
+    // stack is a prime suspect for IddCxAdapterInitAsync -> INVALID_PARAMETER. If removing it fixes adapter
+    // init, the proto control plane moves to EvtIddCxDeviceIoControl (STEP 4) instead of a device interface.
+    let _ = pf_vdisplay_proto::interface_guid_fields; // keep the dep referenced
     // SAFETY: device is the just-created WDFDEVICE.
     let status = unsafe { wdk_iddcx::IddCxDeviceInitialize(device) };
     dbglog!("[pf-vd] IddCxDeviceInitialize -> {status:#x}");
-    if !nt_success(status) {
-        return status;
-    }
-
-    // Expose the owned pf-vdisplay control interface (the host opens this GUID; STEP 4 wires the host
-    // side in lockstep). NOT SudoVDA's GUID.
-    let (d1, d2, d3, d4) = pf_vdisplay_proto::interface_guid_fields();
-    let guid = GUID {
-        Data1: d1,
-        Data2: d2,
-        Data3: d3,
-        Data4: d4,
-    };
-    // SAFETY: device is the just-created WDFDEVICE; guid lives for the call; no reference string.
-    let status = unsafe {
-        call_unsafe_wdf_function_binding!(
-            WdfDeviceCreateDeviceInterface,
-            device,
-            &guid,
-            core::ptr::null()
-        )
-    };
-    dbglog!("[pf-vd] WdfDeviceCreateDeviceInterface -> {status:#x}");
     status
 }