diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5d7b75b7bf..f7944fdfa8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- Blocking app starts if "appLaunchedInForeground" is false. (Android only) ([#2291](https://github.com/getsentry/sentry-dart/pull/2291)
+
 ### Enhancements
 
 - Improve app start integration ([#2266](https://github.com/getsentry/sentry-dart/pull/2266))
diff --git a/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutter.kt b/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutter.kt
index d38872f6ee..4e11cf5cf5 100644
--- a/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutter.kt
+++ b/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutter.kt
@@ -65,7 +65,7 @@ class SentryFlutter(
     }
     data.getIfNotNull<String>("diagnosticLevel") {
       if (options.isDebug) {
-        val sentryLevel = SentryLevel.valueOf(it.toUpperCase(Locale.ROOT))
+        val sentryLevel = SentryLevel.valueOf(it.uppercase(Locale.ROOT))
         options.setDiagnosticLevel(sentryLevel)
       }
     }
diff --git a/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt b/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt
index a10966fd50..a6d4516152 100644
--- a/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt
+++ b/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt
@@ -34,6 +34,8 @@ import io.sentry.protocol.User
 import io.sentry.transport.CurrentDateProvider
 import java.io.File
 import java.lang.ref.WeakReference
+import kotlin.time.DurationUnit
+import kotlin.time.toDuration
 
 class SentryFlutterPlugin : FlutterPlugin, MethodCallHandler, ActivityAware {
   private lateinit var channel: MethodChannel
@@ -171,6 +173,16 @@ class SentryFlutterPlugin : FlutterPlugin, MethodCallHandler, ActivityAware {
 
     val appStartMetrics = AppStartMetrics.getInstance()
 
+    if (!appStartMetrics.isAppLaunchedInForeground ||
+      appStartMetrics.appStartTimeSpan.durationMs > 1.toDuration(DurationUnit.MINUTES).inWholeMilliseconds
+    ) {
+      Log.w(
+        "Sentry",
+        "Invalid app start data: app not launched in foreground or app start took too long (>60s)",
+      )
+      result.success(null)
+    }
+
     val appStartTimeSpan = appStartMetrics.appStartTimeSpan
     val appStartTime = appStartTimeSpan.startTimestamp
     val isColdStart = appStartMetrics.appStartType == AppStartMetrics.AppStartType.COLD