diff --git a/Sources/SwiftOCADevice/OCC/ControlClasses/Managers/SubscriptionManager.swift b/Sources/SwiftOCADevice/OCC/ControlClasses/Managers/SubscriptionManager.swift
index 3f1da67c..b30bf644 100644
--- a/Sources/SwiftOCADevice/OCC/ControlClasses/Managers/SubscriptionManager.swift
+++ b/Sources/SwiftOCADevice/OCC/ControlClasses/Managers/SubscriptionManager.swift
@@ -31,7 +31,7 @@ public class OcaSubscriptionManager: OcaManager {
         _ subscription: AddSubscriptionParameters,
         from controller: AES70OCP1Controller
     ) async throws {
-        try ensureWritable(by: controller)
+        try await ensureWritable(by: controller)
         try await controller.addSubscription(subscription)
     }
 
@@ -39,7 +39,7 @@ public class OcaSubscriptionManager: OcaManager {
         _ subscription: RemoveSubscriptionParameters,
         from controller: AES70OCP1Controller
     ) async throws {
-        try ensureWritable(by: controller)
+        try await ensureWritable(by: controller)
         try await controller.removeSubscription(
             subscription.event,
             subscriber: subscription.subscriber
@@ -47,12 +47,12 @@ public class OcaSubscriptionManager: OcaManager {
     }
 
     func disableNotifications(from controller: AES70OCP1Controller) async throws {
-        try ensureWritable(by: controller)
+        try await ensureWritable(by: controller)
         controller.notificationsEnabled = false
     }
 
     func reenableNotifications(from controller: AES70OCP1Controller) async throws {
-        try ensureWritable(by: controller)
+        try await ensureWritable(by: controller)
         controller.notificationsEnabled = true
     }
 
diff --git a/Sources/SwiftOCADevice/OCC/ControlClasses/Root.swift b/Sources/SwiftOCADevice/OCC/ControlClasses/Root.swift
index 5985a4cb..fbca05d7 100644
--- a/Sources/SwiftOCADevice/OCC/ControlClasses/Root.swift
+++ b/Sources/SwiftOCADevice/OCC/ControlClasses/Root.swift
@@ -86,10 +86,10 @@ open class OcaRoot: CustomStringConvertible {
             let property = self[keyPath: propertyKeyPath] as! (any OcaDevicePropertyRepresentable)
 
             if command.methodID == property.getMethodID {
-                try ensureReadable(by: controller)
+                try await ensureReadable(by: controller)
                 return try await property.get(object: self)
             } else if command.methodID == property.setMethodID {
-                try ensureWritable(by: controller)
+                try await ensureWritable(by: controller)
                 try await property.set(object: self, command: command)
                 return Ocp1Response()
             }
@@ -128,7 +128,11 @@ open class OcaRoot: CustomStringConvertible {
         false
     }
 
-    public func ensureReadable(by controller: AES70OCP1Controller) throws {
+    public func ensureReadable(by controller: AES70OCP1Controller) async throws {
+        if let deviceManager = await deviceDelegate?.deviceManager, deviceManager != self {
+            try await deviceManager.ensureReadable(by: controller)
+        }
+
         switch lockState {
         case .unlocked:
             break
@@ -141,7 +145,11 @@ open class OcaRoot: CustomStringConvertible {
         }
     }
 
-    public func ensureWritable(by controller: AES70OCP1Controller) throws {
+    public func ensureWritable(by controller: AES70OCP1Controller) async throws {
+        if let deviceManager = await deviceDelegate?.deviceManager, deviceManager != self {
+            try await deviceManager.ensureWritable(by: controller)
+        }
+
         switch lockState {
         case .unlocked:
             break
@@ -163,9 +171,13 @@ open class OcaRoot: CustomStringConvertible {
         case .unlocked:
             lockState = .lockedNoWrite(controller)
         case .lockedNoWrite:
-            fallthrough
-        case .lockedNoReadWrite:
             throw Ocp1Error.status(.locked)
+        case let .lockedNoReadWrite(lockholder):
+            guard controller == lockholder else {
+                throw Ocp1Error.status(.locked)
+            }
+            // downgrade lock
+            lockState = .lockedNoWrite(controller)
         }
     }
 
diff --git a/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Block.swift b/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Block.swift
index 7f14bb79..b2335ad7 100644
--- a/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Block.swift
+++ b/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Block.swift
@@ -119,15 +119,15 @@ open class OcaBlock: OcaWorker {
     ) async throws -> Ocp1Response {
         switch command.methodID {
         case OcaMethodID("3.5"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             let members = members.map(\.objectIdentification)
             return try encodeResponse(members)
         case OcaMethodID("3.6"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             let members: [OcaBlockMember] = try await getRecursive(from: controller)
             return try encodeResponse(members)
         case OcaMethodID("3.10"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             let members: [OcaUint16: OcaSignalPath] = try await getRecursive(from: controller)
             return try encodeResponse(members)
         default:
diff --git a/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Matrix.swift b/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Matrix.swift
index 9b94dc45..3598eebd 100644
--- a/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Matrix.swift
+++ b/Sources/SwiftOCADevice/OCC/ControlClasses/Workers/BlocksAndMatrices/Matrix.swift
@@ -198,7 +198,7 @@ open class OcaMatrix: OcaWorker {
     ) async throws -> Ocp1Response {
         switch command.methodID {
         case OcaMethodID("3.3"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             let size = OcaVector2D<OcaMatrixCoordinate>(
                 x: OcaMatrixCoordinate(members.nX),
                 y: OcaMatrixCoordinate(members.nY)
@@ -213,17 +213,17 @@ open class OcaMatrix: OcaWorker {
             )
             return try encodeResponse(matrixSize)
         case OcaMethodID("3.5"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             let members = members.map(defaultValue: OcaInvalidONo, \.?.objectNumber)
             return try encodeResponse(members)
         case OcaMethodID("3.7"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             let coordinates: OcaVector2D<OcaMatrixCoordinate> = try decodeCommand(command)
             let objectNumber = members[Int(coordinates.x), Int(coordinates.y)]?
                 .objectNumber ?? OcaInvalidONo
             return try encodeResponse(objectNumber)
         case OcaMethodID("3.8"):
-            try ensureWritable(by: controller)
+            try await ensureWritable(by: controller)
             struct SetMemberParameters: Codable {
                 var x: OcaMatrixCoordinate
                 var y: OcaMatrixCoordinate
@@ -244,10 +244,10 @@ open class OcaMatrix: OcaWorker {
             }
             members[Int(parameters.x), Int(parameters.y)] = object
         case OcaMethodID("3.9"):
-            try ensureReadable(by: controller)
+            try await ensureReadable(by: controller)
             return try encodeResponse(proxy.objectNumber)
         case OcaMethodID("3.2"):
-            try ensureWritable(by: controller)
+            try await ensureWritable(by: controller)
             let coordinates: OcaVector2D<OcaMatrixCoordinate> = try decodeCommand(command)
             guard coordinates.x < members.nX || coordinates.x == 0xFFFF,
                   coordinates.y < members.nY || coordinates.y == 0xFFFF