diff --git a/MusicBridge.xcodeproj/project.pbxproj b/MusicBridge.xcodeproj/project.pbxproj
index fa33e3a..c8fe7e3 100644
--- a/MusicBridge.xcodeproj/project.pbxproj
+++ b/MusicBridge.xcodeproj/project.pbxproj
@@ -337,6 +337,16 @@
 			"isa" = "PBXBuildFile";
 			"fileRef" = "464F6C65BC2FAB6BCCC77F46";
 		};
+		"7749A66489642A16382E8E42" = {
+			"isa" = "PBXFileReference";
+			"lastKnownFileType" = "sourcecode.swift";
+			"path" = "SystemPlayerTests.swift";
+			"sourceTree" = "<group>";
+		};
+		"340F55A9E43E8FFA66453825" = {
+			"isa" = "PBXBuildFile";
+			"fileRef" = "7749A66489642A16382E8E42";
+		};
 		"8BED860F1BD59C500D215E8D" = {
 			"isa" = "PBXFileReference";
 			"lastKnownFileType" = "sourcecode.swift";
@@ -351,7 +361,7 @@
 			"isa" = "PBXGroup";
 			"path" = "MusicBridgeTests";
 			"sourceTree" = "<group>";
-			"children" = ("C9F705D432CA45B6056BC572", "65CE96DA4162DE4255412BC7", "9819FF7CC21CAAD1BDB8D1B8", "ACD0393DCDDDF044F2966340", "464F6C65BC2FAB6BCCC77F46", "8BED860F1BD59C500D215E8D", "F16D05EC6B29248D2C61ADB1", "4731785CAB9BB914B8834AE6",);
+			"children" = ("C9F705D432CA45B6056BC572", "65CE96DA4162DE4255412BC7", "9819FF7CC21CAAD1BDB8D1B8", "ACD0393DCDDDF044F2966340", "464F6C65BC2FAB6BCCC77F46", "7749A66489642A16382E8E42", "8BED860F1BD59C500D215E8D", "F16D05EC6B29248D2C61ADB1", "4731785CAB9BB914B8834AE6",);
 		};
 		"F16D05EC6B29248D2C61ADB1" = {
 			"isa" = "PBXFileReference";
@@ -525,7 +535,7 @@
 		"AB453A3F0E1490D48374A69A" = {
 			"isa" = "PBXSourcesBuildPhase";
 			"buildActionMask" = 2147483647;
-			"files" = ("1DD7BB0437E9F53586831F22", "E87BA6EF1948C84AC29D8EA8", "BD0B3FAC7F1259D249134283", "17E248E58CB43C680B48DD51", "EFDB280E0B23F7E2A246BC89", "DC1A5B0B94F4C98F1CA36676",);
+			"files" = ("1DD7BB0437E9F53586831F22", "E87BA6EF1948C84AC29D8EA8", "BD0B3FAC7F1259D249134283", "17E248E58CB43C680B48DD51", "EFDB280E0B23F7E2A246BC89", "340F55A9E43E8FFA66453825", "DC1A5B0B94F4C98F1CA36676",);
 			"runOnlyForDeploymentPostprocessing" = 0;
 		};
 		"9AA2A4C344B5C474AF5D336C" = {
diff --git a/MusicBridge/Info.plist b/MusicBridge/Info.plist
index 712246c..4e04652 100644
--- a/MusicBridge/Info.plist
+++ b/MusicBridge/Info.plist
@@ -73,6 +73,6 @@
 		</dict>
 	</dict>
 	<key>MusicBridgeSharedKeychainGroup</key>
-	<string>$(AppIdentifierPrefix)ru.yukinoki.musicbridge.remote-control</string>
+	<string>ru.yukinoki.musicbridge.remote-control</string>
 </dict>
 </plist>
diff --git a/MusicBridge/SystemPlayerManager.swift b/MusicBridge/SystemPlayerManager.swift
index 7944c2e..1ffe405 100644
--- a/MusicBridge/SystemPlayerManager.swift
+++ b/MusicBridge/SystemPlayerManager.swift
@@ -44,21 +44,29 @@ final class SystemPlayerManager: ObservableObject {
     func restore(connection: Connection?) async {
         guard #available(iOS 27.0, *), id == nil, !busy,
               let savedID = UserDefaults.standard.string(forKey: savedIDKey) else { return }
+        busy = true
+        id = savedID
+        let operation = generation
+        defer { if generation == operation { busy = false } }
         do {
             let saved = try SystemPlayerCredentials.load(savedID)
             guard let connection, saved.fingerprint == connection.fingerprint, saved.token == connection.token else {
                 try SystemPlayerCredentials.delete(savedID)
                 UserDefaults.standard.removeObject(forKey: savedIDKey)
                 for session in try await RemoteMediaSession<SystemPlayerAttributes>.sessions() where session.id == savedID { try await session.end() }
+                if generation == operation { id = nil }
                 return
             }
             if let session = try await RemoteMediaSession<SystemPlayerAttributes>.sessions().first(where: { $0.id == savedID }) {
+                guard generation == operation else { return }
                 storage = session; id = savedID; running = true
             } else {
+                guard generation == operation else { return }
                 try SystemPlayerCredentials.delete(savedID)
                 UserDefaults.standard.removeObject(forKey: savedIDKey)
+                id = nil
             }
-        } catch { self.error = BridgeError.describe(error) }
+        } catch { if generation == operation { self.error = BridgeError.describe(error); id = nil } }
     }
 
     func receive(_ state: MediaState, connection: Connection) {
diff --git a/MusicBridgeRemote/Info.plist b/MusicBridgeRemote/Info.plist
index 2a4c9b6..38ec420 100644
--- a/MusicBridgeRemote/Info.plist
+++ b/MusicBridgeRemote/Info.plist
@@ -26,7 +26,7 @@
 		<string>com.apple.nowplaying.remote-media</string>
 	</dict>
 	<key>MusicBridgeSharedKeychainGroup</key>
-	<string>$(AppIdentifierPrefix)ru.yukinoki.musicbridge.remote-control</string>
+	<string>ru.yukinoki.musicbridge.remote-control</string>
 	<key>NSLocalNetworkUsageDescription</key>
 	<string>MusicBridge подключается к вашему ПК, чтобы показывать музыку и управлять воспроизведением.</string>
 	<key>NSAppTransportSecurity</key>
diff --git a/MusicBridgeRemote/MusicBridgeRemote.swift b/MusicBridgeRemote/MusicBridgeRemote.swift
index 8868c3a..640d8df 100644
--- a/MusicBridgeRemote/MusicBridgeRemote.swift
+++ b/MusicBridgeRemote/MusicBridgeRemote.swift
@@ -40,7 +40,7 @@ final class PCMediaSession: RemoteMediaSessionRepresentable {
     }
 
     var playbackSnapshot: MediaPlaybackSnapshot? {
-        MediaPlaybackSnapshot(state: attributes.playing ? .playing(rate: attributes.rate) : .paused,
+        MediaPlaybackSnapshot(state: attributes.playing ? .playing(rate: Float(attributes.rate)) : .paused,
                               elapsedTime: attributes.position, timestamp: attributes.timestamp)
     }
 
diff --git a/MusicBridgeTests/SystemPlayerTests.swift b/MusicBridgeTests/SystemPlayerTests.swift
new file mode 100644
index 0000000..2e562d5
--- /dev/null
+++ b/MusicBridgeTests/SystemPlayerTests.swift
@@ -0,0 +1,54 @@
+import XCTest
+@testable import MusicBridge
+
+@MainActor
+final class SystemPlayerTests: XCTestCase {
+    private func state(_ changes: [String: Any] = [:]) throws -> MediaState {
+        let url = try XCTUnwrap(Bundle(for: Self.self).url(forResource: "state-v1", withExtension: "json"))
+        var json = try XCTUnwrap(JSONSerialization.jsonObject(with: Data(contentsOf: url)) as? [String: Any])
+        changes.forEach { json[$0.key] = $0.value }
+        return try JSONDecoder().decode(MediaState.self, from: JSONSerialization.data(withJSONObject: json))
+    }
+
+    func testSeekConvertsRelativePositionAndClampsToAllowedRange() throws {
+        let state = try state(["startSeconds": 100, "endSeconds": 300, "minSeekSeconds": 110, "maxSeekSeconds": 280])
+        XCTAssertEqual(try SystemPlayerTransport.command(.seek, value: 30, state: state).value, 130)
+        XCTAssertEqual(try SystemPlayerTransport.command(.seek, value: -50, state: state).value, 110)
+        XCTAssertEqual(try SystemPlayerTransport.command(.seek, value: 500, state: state).value, 280)
+        XCTAssertThrowsError(try SystemPlayerTransport.command(.seek, value: .nan, state: state))
+    }
+
+    func testVolumeBoundsAndUnsupportedPlayback() throws {
+        let state = try state()
+        XCTAssertEqual(try SystemPlayerTransport.command(.volume, value: 2, state: state).value, 1)
+        XCTAssertEqual(try SystemPlayerTransport.command(.volume, value: -1, state: state).value, 0)
+        XCTAssertThrowsError(try SystemPlayerTransport.command(.volume, value: .infinity, state: state))
+        XCTAssertThrowsError(try SystemPlayerTransport.command(.play, value: nil, state: state))
+        XCTAssertThrowsError(try SystemPlayerTransport.command(.next, value: nil, state: self.state(["hasSession": false])))
+    }
+
+    func testRemoteSnapshotContainsOnlyPublicPlaybackMetadata() throws {
+        guard #available(iOS 27.0, *) else { throw XCTSkip("Requires NowPlaying") }
+        let snapshot = SystemPlayerAttributes(id: "session", state: try state(["positionSeconds": 130, "startSeconds": 100, "endSeconds": 300]))
+        XCTAssertEqual(snapshot.position, 30)
+        XCTAssertEqual(snapshot.duration, 200)
+        let json = try XCTUnwrap(JSONSerialization.jsonObject(with: JSONEncoder().encode(snapshot)) as? [String: Any])
+        XCTAssertEqual(Set(json.keys), Set(["id", "title", "artist", "source", "playing", "rate", "position", "duration", "timestamp", "capabilities", "volume", "hasSession"]))
+    }
+
+    func testRevokedSessionDoesNotSendCommandAndNextIsSentOnce() async throws {
+        let url = try XCTUnwrap(Bundle(for: Self.self).url(forResource: "tls-fixture", withExtension: "json"))
+        let fixtures = try JSONDecoder().decode([String: [String: String]].self, from: Data(contentsOf: url))
+        let f = try XCTUnwrap(fixtures["valid"])
+        let client = BridgeClient(try Connection(endpoint: XCTUnwrap(f["endpoint"]), fingerprint: XCTUnwrap(f["fingerprint"]), token: "live-system-next"))
+        defer { client.close() }
+        do {
+            _ = try await SystemPlayerTransport.execute(.next, client: client) { throw BridgeError.unauthorized }
+            XCTFail("Revoked session must be rejected")
+        } catch BridgeError.unauthorized { }
+        let unchanged = try await client.state()
+        XCTAssertEqual(unchanged.title, "Track 0")
+        let updated = try await SystemPlayerTransport.execute(.next, client: client)
+        XCTAssertEqual(updated.title, "Track 1")
+    }
+}
diff --git a/RemoteShared/SystemPlayerCredentials.swift b/RemoteShared/SystemPlayerCredentials.swift
index 6f19a0f..69dbc1d 100644
--- a/RemoteShared/SystemPlayerCredentials.swift
+++ b/RemoteShared/SystemPlayerCredentials.swift
@@ -2,13 +2,33 @@ import Foundation
 import Security
 
 enum SystemPlayerCredentials {
+    // Derive the signing prefix from our own default Keychain group. Info.plist
+    // build substitutions cannot know the team that later re-signs an IPA.
+    private static func signingPrefix() throws -> String {
+        let marker: [String: Any] = [kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: "MusicBridge.signing-prefix.v1", kSecAttrAccount as String: "prefix"]
+        let status = SecItemAdd(marker.merging([kSecValueData as String: Data(),
+            kSecAttrAccessible as String: kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly]) { _, v in v } as CFDictionary, nil)
+        guard status == errSecSuccess || status == errSecDuplicateItem else { throw failure(status) }
+        var result: CFTypeRef?
+        let read = SecItemCopyMatching(marker.merging([kSecReturnAttributes as String: true,
+            kSecMatchLimit as String: kSecMatchLimitOne]) { _, v in v } as CFDictionary, &result)
+        guard read == errSecSuccess else { throw failure(read) }
+        guard let attributes = result as? [String: Any],
+              let group = attributes[kSecAttrAccessGroup as String] as? String,
+              let separator = group.firstIndex(of: "."), separator != group.startIndex else {
+            throw failure(errSecMissingEntitlement)
+        }
+        return String(group[...separator])
+    }
+
     private static func query(_ id: String) throws -> [String: Any] {
-        guard let group = Bundle.main.object(forInfoDictionaryKey: "MusicBridgeSharedKeychainGroup") as? String,
-              !group.isEmpty, !group.contains("$(") else {
+        guard let suffix = Bundle.main.object(forInfoDictionaryKey: "MusicBridgeSharedKeychainGroup") as? String,
+              suffix == "ru.yukinoki.musicbridge.remote-control" else {
             throw BridgeError.message("Подпись приложения не настроила общий Keychain для системного пульта.")
         }
         return [kSecClass as String: kSecClassGenericPassword, kSecAttrService as String: "MusicBridge.system-player.v1",
-                kSecAttrAccount as String: id, kSecAttrAccessGroup as String: group]
+                kSecAttrAccount as String: id, kSecAttrAccessGroup as String: try signingPrefix() + suffix]
     }
 
     static func save(_ connection: Connection, id: String) throws {
diff --git a/tools/generate_project.py b/tools/generate_project.py
index 6135ebb..ecadc98 100644
--- a/tools/generate_project.py
+++ b/tools/generate_project.py
@@ -162,11 +162,11 @@ widget_info = dict(CFBundleDevelopmentRegion="ru", CFBundleDisplayName="MusicBri
                    NSExtension=dict(NSExtensionPointIdentifier="com.apple.widgetkit-extension"))
 (ROOT / "MusicBridgeWidgets" / "Info.plist").write_bytes(plistlib.dumps(widget_info, sort_keys=False))
 shared_group_name = "$(AppIdentifierPrefix)ru.yukinoki.musicbridge.remote-control"
-info["MusicBridgeSharedKeychainGroup"] = shared_group_name
+info["MusicBridgeSharedKeychainGroup"] = "ru.yukinoki.musicbridge.remote-control"
 (ROOT / "MusicBridge" / "Info.plist").write_bytes(plistlib.dumps(info, sort_keys=False))
 remote_info = {k: v for k, v in widget_info.items() if k != "NSExtension"}
 remote_info.update(EXAppExtensionAttributes=dict(EXExtensionPointIdentifier="com.apple.nowplaying.remote-media"),
-                   MusicBridgeSharedKeychainGroup=shared_group_name,
+                   MusicBridgeSharedKeychainGroup=info["MusicBridgeSharedKeychainGroup"],
                    NSLocalNetworkUsageDescription=info["NSLocalNetworkUsageDescription"],
                    NSAppTransportSecurity=info["NSAppTransportSecurity"])
 (ROOT / "MusicBridgeRemote" / "Info.plist").write_bytes(plistlib.dumps(remote_info, sort_keys=False))
diff --git a/tools/verify_ipa.py b/tools/verify_ipa.py
index f5fd8b6..0291924 100644
--- a/tools/verify_ipa.py
+++ b/tools/verify_ipa.py
@@ -47,6 +47,25 @@ with zipfile.ZipFile(path) as archive:
             platforms.append(struct.unpack_from("<I", binary, offset + 8)[0])
         offset += size
     assert platforms == [2], "Widget is not built for iOS devices"
+    remote_path = prefix + "Extensions/MusicBridgeRemote.appex/"
+    remote = plistlib.loads(archive.read(remote_path + "Info.plist"))
+    assert remote["CFBundleIdentifier"] == info["CFBundleIdentifier"] + ".remote"
+    assert remote["CFBundleShortVersionString"] == info["CFBundleShortVersionString"]
+    assert remote["CFBundleVersion"] == info["CFBundleVersion"]
+    assert remote["MinimumOSVersion"] == "27.0"
+    assert remote["EXAppExtensionAttributes"]["EXExtensionPointIdentifier"] == "com.apple.nowplaying.remote-media"
+    assert remote["MusicBridgeSharedKeychainGroup"] == info["MusicBridgeSharedKeychainGroup"] == "ru.yukinoki.musicbridge.remote-control"
+    binary = archive.read(remote_path + remote["CFBundleExecutable"])
+    assert struct.unpack_from("<II", binary) == (0xFEEDFACF, 0x0100000C)
+    offset, platforms = 32, []
+    for _ in range(struct.unpack_from("<I", binary, 16)[0]):
+        command, size = struct.unpack_from("<II", binary, offset)
+        assert size >= 8 and offset + size <= len(binary)
+        if command == 0x32:
+            platforms.append(struct.unpack_from("<I", binary, offset + 8)[0])
+        offset += size
+    assert platforms == [2], "Remote extension is not built for iOS devices"
 print(f"PASS: {path.name}: valid IPA, iPhoneOS ARM64, iOS 17+, ru.yukinoki.musicbridge.")
 print("PASS: embedded WidgetKit extension, matching version, ARM64 iPhoneOS and Live Activities support.")
-print("Requires local signing with Sideloadly before installation on an iPhone.")
+print("PASS: embedded iOS 27 NowPlaying ExtensionKit extension and matching shared Keychain metadata.")
+print("Requires signing all extensions and shared Keychain entitlements before installation.")