fix: SharedPreferences OOM + low-RAM onboarding for mid-range devices

android/app/src/main/AndroidManifest.xml

@@ -37,7 +37,7 @@
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="Nova"
-
+        android:largeHeap="true"
         android:supportsRtl="true"
         android:theme="@style/LaunchTheme"
         tools:targetApi="34">

android/app/src/main/kotlin/dev/nova/assistant/MainActivity.kt

@@ -82,6 +82,7 @@ class MainActivity : FlutterActivity() {
                                 "pssKb" to pssKb,
                                 "rssKb" to pssKb,
                                 "availMemMb" to (info.availMem / (1024 * 1024)),
+                                "totalMemMb" to (info.totalMem / (1024 * 1024)),
                             )
                         )
                     }

android/app/src/main/kotlin/dev/nova/assistant/NovaApplication.kt

@@ -1,9 +1,173 @@
 package dev.nova.assistant
 
 import android.app.Application
+import android.util.Log
+import java.io.BufferedInputStream
+import java.io.BufferedOutputStream
+import java.io.File
+import java.io.FileInputStream
+import java.io.FileOutputStream
 
+/**
+ * Scrubs oversized chat-history keys from Flutter SharedPreferences **without**
+ * calling [getSharedPreferences]. Loading a 100MB+ prefs XML OOMs during
+ * KXmlParser (POCO F1 / mid-RAM devices).
+ */
 class NovaApplication : Application() {
     override fun onCreate() {
         super.onCreate()
+        scrubOversizedFlutterPrefs()
     }
-}
+
+    private fun scrubOversizedFlutterPrefs() {
+        val prefsFile = File(dataDir, "shared_prefs/$FLUTTER_PREFS.xml")
+        val size = if (prefsFile.exists()) prefsFile.length() else 0L
+        // #region agent log
+        Log.i(
+            TAG,
+            "AGENT_DBG session=7abc09 hyp=A scrub start size=$size path=${prefsFile.absolutePath}",
+        )
+        // #endregion
+        if (!prefsFile.exists() || size == 0L) return
+
+        try {
+            var removed = false
+            for (key in listOf(CONVERSATIONS_KEY, OLD_CHAT_KEY)) {
+                if (streamRemoveStringEntry(prefsFile, key)) {
+                    removed = true
+                    // #region agent log
+                    Log.i(TAG, "AGENT_DBG session=7abc09 hyp=A removed key=$key")
+                    // #endregion
+                }
+            }
+
+            val after = prefsFile.length()
+            // #region agent log
+            Log.i(
+                TAG,
+                "AGENT_DBG session=7abc09 hyp=A scrub done removed=$removed sizeAfter=$after",
+            )
+            // #endregion
+
+            if (after > MAX_SAFE_PREFS_BYTES) {
+                // Do not copyTo() a huge file (that also OOMs). Just replace.
+                prefsFile.delete()
+                prefsFile.writeText(EMPTY_PREFS_XML)
+                // #region agent log
+                Log.w(
+                    TAG,
+                    "AGENT_DBG session=7abc09 hyp=A wiped prefs after=$after",
+                )
+                // #endregion
+            }
+        } catch (e: Exception) {
+            Log.e(TAG, "AGENT_DBG session=7abc09 hyp=A scrub failed", e)
+            try {
+                prefsFile.writeText(EMPTY_PREFS_XML)
+            } catch (_: Exception) {
+                // User must clear app data.
+            }
+        }
+    }
+
+    /**
+     * Removes `<string name="KEY">…</string>` via streaming so the huge value
+     * is never materialized as a Java String.
+     */
+    private fun streamRemoveStringEntry(prefsFile: File, key: String): Boolean {
+        val open = """<string name="$key">""".toByteArray(Charsets.UTF_8)
+        val close = "</string>".toByteArray(Charsets.UTF_8)
+        val tmp = File(prefsFile.parent, "${prefsFile.name}.tmp")
+        var found = false
+
+        FileInputStream(prefsFile).use { fis ->
+            BufferedInputStream(fis, 256 * 1024).use { input ->
+                FileOutputStream(tmp).use { fos ->
+                    BufferedOutputStream(fos, 256 * 1024).use { output ->
+                        val buffer = ByteArray(256 * 1024)
+                        val pending = ArrayList<Byte>(open.size)
+                        var openIdx = 0
+                        var skipping = false
+                        var closeIdx = 0
+
+                        while (true) {
+                            val n = input.read(buffer)
+                            if (n < 0) break
+                            var i = 0
+                            while (i < n) {
+                                val byte = buffer[i]
+
+                                if (skipping) {
+                                    if (byte == close[closeIdx]) {
+                                        closeIdx++
+                                        if (closeIdx == close.size) {
+                                            skipping = false
+                                            closeIdx = 0
+                                            found = true
+                                        }
+                                    } else {
+                                        closeIdx = if (byte == close[0]) 1 else 0
+                                    }
+                                    i++
+                                    continue
+                                }
+
+                                if (byte == open[openIdx]) {
+                                    pending.add(byte)
+                                    openIdx++
+                                    if (openIdx == open.size) {
+                                        skipping = true
+                                        openIdx = 0
+                                        pending.clear()
+                                    }
+                                    i++
+                                    continue
+                                }
+
+                                if (openIdx > 0) {
+                                    for (p in pending) {
+                                        output.write(p.toInt())
+                                    }
+                                    pending.clear()
+                                    openIdx = 0
+                                    continue
+                                }
+
+                                output.write(byte.toInt())
+                                i++
+                            }
+                        }
+
+                        if (!skipping) {
+                            for (p in pending) {
+                                output.write(p.toInt())
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        if (found) {
+            if (!tmp.renameTo(prefsFile)) {
+                tmp.copyTo(prefsFile, overwrite = true)
+                tmp.delete()
+            }
+        } else {
+            tmp.delete()
+        }
+
+        return found
+    }
+
+    companion object {
+        private const val TAG = "NovaApplication"
+        private const val FLUTTER_PREFS = "FlutterSharedPreferences"
+        private const val CONVERSATIONS_KEY = "flutter.conversations"
+        private const val OLD_CHAT_KEY = "flutter.chat_history"
+        private const val MAX_SAFE_PREFS_BYTES = 4L * 1024L * 1024L
+        private const val EMPTY_PREFS_XML =
+            "<?xml version='1.0' encoding='utf-8' standalone='yes' ?>\n" +
+                "<map>\n</map>\n"
+    }
+}

docs/models.md

@@ -57,4 +57,24 @@ When a thread gets long, **Compact context** (manual button in chat) or **Auto-c
 | 8 GB+ | Gemma 4 E2B OK; close heavy apps first |
 | Debug all day | Enable battery/idle unload; avoid continuous screen capture |
 
+Onboarding uses **total device RAM** (not only free RAM): phones under ~6.5 GB
+default to **SmolLM** so a wiped POCO F1 does not start a 2.4 GB Gemma 4 download
+it cannot load for chat.
+
 Android idle unload is shorter (~2 minutes) to reduce LMK pressure.
+
+## On-device image generation (not in this build)
+
+Repos such as
+[FLUX.2-klein-4B-LiteRT](https://huggingface.co/litert-community/FLUX.2-klein-4B-LiteRT)
+and
+[Z-Image-Turbo-LiteRT](https://huggingface.co/litert-community/Z-Image-Turbo-LiteRT)
+are **LiteRT `CompiledModel` multi-graph diffusion pipelines** (many `.tflite`
+chunks + host tokenizer/scheduler), not `flutter_gemma` / LiteRT-LM chat
+(`.litertlm` / `.task`) models.
+
+Nova’s stack only runs LLM/VLM chat via `flutter_gemma`. Shipping those image
+models would mean a separate native LiteRT GPU pipeline, multi‑GB downloads, and
+phones in the Pixel 8a / 8 GB+ class for usable demos — out of scope for the
+current APK (and unsuitable for POCO F1). Prefer **remote LAN** or a PC host
+for image generation for now.

lib/main.dart

@@ -27,13 +27,28 @@ import 'package:nova_assistant/services/chat_history_service.dart';
 import 'package:nova_assistant/services/widget_service.dart';
 import 'package:nova_assistant/models/conversation.dart';
 import 'package:nova_assistant/models/user_preferences.dart';
+import 'package:nova_assistant/utils/agent_debug_log.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
 
   try {
+    // #region agent log
+    await AgentDebugLog.log(
+      hypothesisId: 'A',
+      location: 'main.dart:beforePrefs',
+      message: 'About to call SharedPreferences.getInstance',
+    );
+    // #endregion
     await SharedPreferences.getInstance();
+    // #region agent log
+    await AgentDebugLog.log(
+      hypothesisId: 'A',
+      location: 'main.dart:afterPrefs',
+      message: 'SharedPreferences.getInstance succeeded',
+    );
+    // #endregion
 
     await FlutterGemma.initialize(
       inferenceEngines: const [LiteRtLmEngine(), MediaPipeEngine()],
@@ -55,6 +70,7 @@ void main() async {
     await TtsService.instance.initialize();
     await PromptPresetsService.instance.initialize();
 
+    await ModelOrchestrator.instance.applyRamAwareModelDefaults();
     _prefetchModels();
   } catch (e) {
     debugPrint('Initialization error: $e');

lib/screens/assistant_screen.dart

@@ -1943,11 +1943,14 @@ class _AssistantScreenState extends State<AssistantScreen>
             ),
           ),
           const SizedBox(width: 6),
-          Text(
-            _status,
-            style: TextStyle(fontSize: 11, color: Colors.grey[500]),
+          Expanded(
+            child: Text(
+              _status,
+              maxLines: 1,
+              overflow: TextOverflow.ellipsis,
+              style: TextStyle(fontSize: 11, color: Colors.grey[500]),
+            ),
           ),
-          const Spacer(),
           if (_thinkingMode)
             Container(
               padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),