fix: tick native watchdog before SetFormat to prevent black screen

osu.Android/LogManagement.cs

@@ -315,6 +315,25 @@ public static void NormaliseFrameworkIniRendererDefault()
                 string sentinelPath = Path.Combine(root, renderer_migration_sentinel);
                 if (File.Exists(sentinelPath)) return;
 
+                // On fresh installs (no framework.ini yet), default to OpenGL instead of Vulkan.
+                // Vulkan causes black screens on several Adreno GPU families (7xx series in
+                // particular) because the Veldrid Vulkan backend either times out its 5s
+                // SurfaceHandle poll or hands a stale ANativeWindow to vkCreateAndroidSurfaceKHR.
+                // OpenGL ES is the safer default; users can switch to Vulkan in Settings.
+                string iniPath = Path.Combine(root, "framework.ini");
+                if (!File.Exists(iniPath))
+                {
+                    try
+                    {
+                        File.WriteAllText(iniPath, "Renderer = OpenGL" + Environment.NewLine);
+                        Debug.WriteLine("[osu!] Fresh install — defaulted renderer to OpenGL.");
+                    }
+                    catch (Exception e)
+                    {
+                        Debug.WriteLine($"[osu!] Could not write fresh-install renderer default: {e.Message}");
+                    }
+                }
+
                 tryDropSentinel(sentinelPath);
             }
             catch (Exception e)

osu.Android/OsuGameActivity.cs

@@ -21,6 +21,7 @@
 using osu.Framework.Android;
 using osu.Game.Database;
 using osu.Framework.Logging;
+using osu.Android.Native;
 
 namespace osu.Android
 {
@@ -891,9 +892,6 @@ public void SurfaceChanged(ISurfaceHolder holder, global::Android.Graphics.Forma
                 setFormatPending = true;
                 setFormatAttempts = 1;
 
-                // Log to Runtime so the mid-session RGB565 reset is visible in the main log
-                // (and therefore in the notification overlay). Performance log gets the same
-                // entry for correlation with display-mode and frame-timing data.
                 string rgb565Message =
                     "[osu!] Android surface pixel format RGB565 detected (Vulkan path) — " +
                     "requesting RGBA8888 and triggering a surface recreate. " +
@@ -902,6 +900,27 @@ public void SurfaceChanged(ISurfaceHolder holder, global::Android.Graphics.Forma
                 Logger.Log(rgb565Message, LoggingTarget.Runtime, LogLevel.Important);
                 Logger.Log(rgb565Message, LoggingTarget.Performance, LogLevel.Important);
 
+                // Tick the native watchdog BEFORE calling SetFormat. SetFormat triggers a
+                // synchronous surface teardown on the UI thread that can block for hundreds
+                // of milliseconds. During this window the Update thread may not get a chance
+                // to send a heartbeat (especially during startup when the runtime is under
+                // heavy load), and the native watchdog (10s default) would fire, killing the
+                // process and producing a black screen.
+                //
+                // Calling Heartbeat() here resets the watchdog timer from the UI thread,
+                // giving SetFormat time to complete without triggering a false positive.
+                // The native watchdog checks g_lastHeartbeatMonotonicSec which is updated
+                // by a simple atomic store — safe to call from any thread.
+                try
+                {
+                    NativeWatchdog.Heartbeat();
+                    Debug.WriteLine("[osu!] Native watchdog heartbeat ticked before SetFormat(RGBA8888)");
+                }
+                catch (Exception e)
+                {
+                    Debug.WriteLine($"[osu!] NativeWatchdog.Heartbeat failed (non-fatal): {e.Message}");
+                }
+
                 try
                 {
                     holder.SetFormat(global::Android.Graphics.Format.Rgba8888);
@@ -911,17 +930,13 @@ public void SurfaceChanged(ISurfaceHolder holder, global::Android.Graphics.Forma
                     Debug.WriteLine($"[osu!] Failed to request RGBA8888 format change for Vulkan: {e.Message}");
                 }
 
-                // The SetFormat call above queues a SurfaceDestroyed→SurfaceCreated cycle.
-                // Reset the surface event so GetSurfaceGlobalRef() does NOT unblock yet —
-                // the current Surface handle is about to be invalidated, and any caller that
-                // receives it would forward a dangling pointer into the Vulkan driver.
-                // The event will be re-set when SurfaceChanged fires again for the new
-                // RGBA8888 Surface; the normal-path surfaceEvent.Set() at the end of this
-                // method (lines below the if/else-if guard) handles that on the next call.
-                // We must NOT fall through to the width/height check, because that would
-                // signal the event with the old (about-to-die) surface dimensions.
+                Debug.WriteLine("[osu!] Native surface format change requested (RGB565→RGBA8888)");
+
+                // Reset the surface event so GetSurfaceGlobalRef() does NOT unblock with the
+                // old (about-to-be-invalidated) surface handle. The event will be re-set when
+                // SurfaceChanged fires again for the new RGBA8888 surface.
                 surfaceEvent.Reset();
-                Debug.WriteLine("[osu!] Native surface signal reset (RGB565→RGBA8888 format change pending)");
+
                 return;
             }