Try fixing the RunOniOS failing test stage

.config/dotnet-tools.json

@@ -24,7 +24,7 @@
       "rollForward": false
     },
     "microsoft.dotnet.xharness.cli": {
-      "version": "10.0.0-prerelease.25575.2",
+      "version": "11.0.0-prerelease.25603.1",
       "commands": [
         "xharness"
       ],

src/TestUtils/src/Microsoft.Maui.IntegrationTests/Apple/Simulator.cs

@@ -19,7 +19,34 @@ public string GetUDID()
 		public bool Launch()
 		{
 			ToolRunner.Run(XCRunTool, $"simctl boot {GetUDID()}", out int exitCode, timeoutInSeconds: 30);
-			return exitCode == 0;
+			if (exitCode != 0)
+				return false;
+
+			// Wait for the simulator to be fully booted before returning
+			// The boot command can return before the simulator is ready to accept app launches
+			return WaitForSimulatorReady(timeoutInSeconds: 60);
+		}
+
+		bool WaitForSimulatorReady(int timeoutInSeconds = 60)
+		{
+			var udid = GetUDID();
+			var startTime = DateTime.UtcNow;
+			var timeout = TimeSpan.FromSeconds(timeoutInSeconds);
+
+			while (DateTime.UtcNow - startTime < timeout)
+			{
+				var output = ToolRunner.Run(XCRunTool, $"simctl bootstatus {udid}", out int exitCode, timeoutInSeconds: 10);
+				if (exitCode == 0)
+					return true;
+
+				// Print diagnostic output to help troubleshoot boot issues
+				TestContext.WriteLine($"Simulator not ready yet: {output}");
+
+				// Wait a bit before checking again
+				System.Threading.Thread.Sleep(2000);
+			}
+
+			return false;
 		}
 
 		public bool Shutdown()

src/TestUtils/src/Microsoft.Maui.IntegrationTests/AppleTemplateTests.cs

@@ -51,7 +51,6 @@ public void RunOniOS(string id, string config, string framework, string runtimeI
 				buildProps.Add("PublishAot=true");
 				buildProps.Add("PublishAotUsingRuntimePack=true"); // TODO: This parameter will become obsolete https://github.com/dotnet/runtime/issues/87060
 				buildProps.Add("_IsPublishing=true"); // using dotnet build with -p:_IsPublishing=true enables targeting simulators
-				buildProps.Add($"RuntimeIdentifier={runtimeIdentifier}");
 				buildProps.Add("IlcTreatWarningsAsErrors=false"); // TODO: Remove this once all warnings are fixed https://github.com/dotnet/maui/issues/19397
 			}
 
@@ -61,12 +60,13 @@ public void RunOniOS(string id, string config, string framework, string runtimeI
 				buildProps.Add("TrimmerSingleWarn=false"); // Disable trimmer warnings for iOS full trimming builds due to ObjCRuntime issues
 			}
 
-			Assert.IsTrue(DotnetInternal.Build(projectFile, config, framework: $"{framework}-ios", properties: buildProps),
+			Assert.IsTrue(DotnetInternal.Build(projectFile, config, framework: $"{framework}-ios", properties: buildProps, runtimeIdentifier: runtimeIdentifier),
 				$"Project {Path.GetFileName(projectFile)} failed to build. Check test output/attachments for errors.");
 
 			var appFile = Path.Combine(projectDir, "bin", config, $"{framework}-ios", runtimeIdentifier, $"{Path.GetFileName(projectDir)}.app");
 
-			Assert.IsTrue(XHarness.RunAppleForTimeout(appFile, Path.Combine(projectDir, "xh-results"), TestSimulator.XHarnessID),
+			// Pass the simulator UDID to help XHarness use our already-booted simulator
+			Assert.IsTrue(XHarness.RunAppleForTimeout(appFile, Path.Combine(projectDir, "xh-results"), TestSimulator.XHarnessID, TestSimulator.GetUDID()),
 				$"Project {Path.GetFileName(projectFile)} failed to run. Check test output/attachments for errors.");
 		}
 	}

src/TestUtils/src/Microsoft.Maui.IntegrationTests/Utilities/XHarness.cs

@@ -21,12 +21,14 @@ public static bool RunAndroid(string packageName, string resultDir, int expected
 		/// <param name="appPath"></param>
 		/// <param name="resultDir"></param>
 		/// <param name="targetDevice"></param>
+		/// <param name="deviceUDID">Optional UDID of a specific already-booted simulator to use.</param>
 		/// <param name="launchTimeoutSeconds"></param>
 		/// <returns>True if the app launch command timed out, false if it exits early.</returns>
-		public static bool RunAppleForTimeout(string appPath, string resultDir, string targetDevice, int launchTimeoutSeconds = 75)
+		public static bool RunAppleForTimeout(string appPath, string resultDir, string targetDevice, string? deviceUDID = null, int launchTimeoutSeconds = 75)
 		{
 			var timeoutString = TimeSpan.FromSeconds(launchTimeoutSeconds).ToString();
-			var args = $"apple run --app=\"{appPath}\" --output-directory=\"{resultDir}\" --target={targetDevice} --timeout=\"{timeoutString}\" --verbosity=Debug";
+			var deviceArg = string.IsNullOrEmpty(deviceUDID) ? "" : $" --device=\"{deviceUDID}\"";
+			var args = $"apple run --app=\"{appPath}\" --output-directory=\"{resultDir}\" --target={targetDevice}{deviceArg} --timeout=\"{timeoutString}\" --verbosity=Debug";
 			var xhOutput = RunForOutput(args, out int exitCode, launchTimeoutSeconds + 30);
 
 			var launchLogMatch = false;