diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index e12cf50..7169337 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -56,6 +56,6 @@ dependencies {
     implementation("androidx.appcompat:appcompat:1.7.0")
     implementation("com.google.android.material:material:1.12.0")
     implementation("androidx.activity:activity-ktx:1.9.0")
-    implementation("androidx.work:work-runtime-ktx:2.9.1")
+    implementation("androidx.work:work-runtime-ktx:2.11.2")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.9.0")
 }
diff --git a/sdk/build.gradle.kts b/sdk/build.gradle.kts
index 362f4eb..a86a9da 100644
--- a/sdk/build.gradle.kts
+++ b/sdk/build.gradle.kts
@@ -105,7 +105,7 @@ dependencies {
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.9.0")
     implementation("com.squareup.okhttp3:okhttp:4.12.0")
     implementation("androidx.annotation:annotation:1.8.2")
-    implementation("androidx.work:work-runtime-ktx:2.9.1")
+    implementation("androidx.work:work-runtime-ktx:2.11.2")
     implementation("androidx.core:core-ktx:1.13.1")
 
     testImplementation("junit:junit:4.13.2")
@@ -115,7 +115,7 @@ dependencies {
     testImplementation("androidx.test:core:1.6.1")
     testImplementation("androidx.test.ext:junit:1.2.1")
     testImplementation("io.mockk:mockk:1.13.13")
-    testImplementation("androidx.work:work-testing:2.9.1")
+    testImplementation("androidx.work:work-testing:2.11.2")
 
     androidTestImplementation("androidx.test.ext:junit:1.2.1")
     androidTestImplementation("androidx.test:runner:1.6.2")
diff --git a/sdk/src/main/kotlin/com/soniqo/speech/ModelManager.kt b/sdk/src/main/kotlin/com/soniqo/speech/ModelManager.kt
index 53ab5f5..773173a 100644
--- a/sdk/src/main/kotlin/com/soniqo/speech/ModelManager.kt
+++ b/sdk/src/main/kotlin/com/soniqo/speech/ModelManager.kt
@@ -75,9 +75,10 @@ object ModelManager {
      * and passes [isValidModel] (right ONNX magic, above the per-file size
      * floor) and the cached version matches [MODEL_VERSION].
      *
-     * Cheap and side-effect free — does not start a download. Used by paths
-     * that must answer "are we ready?" without blocking, e.g.
-     * `SpeechRecognitionService.onCheckRecognitionSupport()`.
+     * Cheap and side-effect free — does not start a download. Use this from
+     * `SpeechRecognitionService.onCheckRecognitionSupport()` (or any path
+     * that must not block) to decide whether to invoke [ensureModels] /
+     * `ModelDownloadWorker` first.
      */
     fun areModelsReady(
         context: Context,
@@ -102,6 +103,10 @@ object ModelManager {
         }
     }
 
+    /** Path to the model directory for [precision], without downloading. */
+    fun modelDir(context: Context): String =
+        File(context.filesDir, "models").absolutePath
+
     /** Returns the model directory path, downloading models if needed. */
     suspend fun ensureModels(
         context: Context,
@@ -120,8 +125,10 @@ object ModelManager {
             dir.resolve("voices").listFiles()?.forEach { it.delete() }
         }
 
-        // Clean up leftover partial downloads from previous crashes
-        dir.walk().filter { it.extension == "tmp" }.forEach { it.delete() }
+        // Note: leftover .tmp files are intentionally preserved here. If a
+        // previous run was interrupted, downloadFile resumes via Range:
+        // bytes=N- on the next attempt. Stale .tmp from an old MODEL_VERSION
+        // is already wiped above.
 
         val fileList = models(precision)
         // FP32 encoder needs the external data file
@@ -235,8 +242,11 @@ object ModelManager {
             }
         }
 
-        // All retries exhausted — clean up partial file and throw
-        tmp.delete()
+        // All retries exhausted — preserve the partial .tmp so the next
+        // ensureModels() call can pick up where this one left off via the
+        // Range: header. Particularly important when called from
+        // ModelDownloadWorker, where Result.retry() spins up a fresh
+        // ensureModels() invocation after WorkManager's backoff window.
         throw IOException("Download failed after $MAX_RETRIES attempts: ${lastException?.message}", lastException)
     }
 
diff --git a/sdk/src/main/kotlin/com/soniqo/speech/service/SpeechRecognitionService.kt b/sdk/src/main/kotlin/com/soniqo/speech/service/SpeechRecognitionService.kt
index ec08969..116cdd6 100644
--- a/sdk/src/main/kotlin/com/soniqo/speech/service/SpeechRecognitionService.kt
+++ b/sdk/src/main/kotlin/com/soniqo/speech/service/SpeechRecognitionService.kt
@@ -17,6 +17,9 @@ import android.speech.RecognizerIntent
 import android.speech.SpeechRecognizer
 import android.util.Log
 import androidx.annotation.RequiresApi
+import androidx.work.WorkInfo
+import androidx.work.WorkManager
+import audio.soniqo.speech.ModelDownloadWorker
 import audio.soniqo.speech.ModelManager
 import audio.soniqo.speech.ModelPrecision
 import audio.soniqo.speech.SpeechConfig
@@ -29,8 +32,11 @@ import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.cancelAndJoin
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import java.io.IOException
 import java.util.concurrent.atomic.AtomicBoolean
 
 /**
@@ -256,9 +262,39 @@ open class SpeechRecognitionService : RecognitionService() {
     protected open fun createPipeline(config: SpeechConfig): SpeechPipeline =
         SpeechPipeline(config)
 
-    /** Resolve the model directory. Overridden in tests to skip the download. */
-    protected open suspend fun resolveModelDir(): String =
-        ModelManager.ensureModels(this, ModelPrecision.INT8)
+    /**
+     * Resolve the model directory. If models aren't on disk yet we delegate
+     * to [ModelDownloadWorker] (which runs as a foreground service so the
+     * download survives the bind from Gboard timing out) and suspend until
+     * it reports a terminal state. Suspension is bound to this session's
+     * coroutine — if the framework cancels the request, the worker keeps
+     * running on its own and serves the *next* invocation immediately.
+     *
+     * Overridden in tests to skip the download.
+     */
+    protected open suspend fun resolveModelDir(): String {
+        val ctx = applicationContext
+        if (ModelManager.areModelsReady(ctx, ModelPrecision.INT8)) {
+            return ModelManager.modelDir(ctx)
+        }
+        Log.i(TAG, "models not ready — delegating to ModelDownloadWorker")
+        val workId = ModelDownloadWorker.enqueue(ctx, ModelPrecision.INT8)
+        val info = WorkManager.getInstance(ctx)
+            .getWorkInfoByIdFlow(workId)
+            .filterNotNull()
+            .first { it.state.isFinished }
+        return when (info.state) {
+            WorkInfo.State.SUCCEEDED -> info.outputData
+                .getString(ModelDownloadWorker.KEY_MODEL_DIR)
+                ?: throw IllegalStateException("worker succeeded but no model dir")
+            WorkInfo.State.FAILED -> throw IOException(
+                info.outputData.getString(ModelDownloadWorker.KEY_ERROR)
+                    ?: "model download failed",
+            )
+            WorkInfo.State.CANCELLED -> throw IllegalStateException("model download cancelled")
+            else -> throw IllegalStateException("unexpected worker state: ${info.state}")
+        }
+    }
 
     /**
      * Open the microphone. Returns null when the format is unsupported on this
diff --git a/sdk/src/test/kotlin/audio/soniqo/speech/ModelManagerDownloadTest.kt b/sdk/src/test/kotlin/audio/soniqo/speech/ModelManagerDownloadTest.kt
index 0bd6b69..af18ec0 100644
--- a/sdk/src/test/kotlin/audio/soniqo/speech/ModelManagerDownloadTest.kt
+++ b/sdk/src/test/kotlin/audio/soniqo/speech/ModelManagerDownloadTest.kt
@@ -99,7 +99,7 @@ class ModelManagerDownloadTest {
             }
         }
 
-        tmp.delete()
+        // Preserve tmp for resume on next attempt — mirrors production.
         throw IOException("Failed after $maxRetries attempts: ${lastException?.message}", lastException)
     }
 
@@ -155,17 +155,28 @@ class ModelManagerDownloadTest {
     }
 
     @Test
-    fun `cleans up tmp file after all retries fail`() {
-        server.enqueue(MockResponse().setResponseCode(500))
-        server.enqueue(MockResponse().setResponseCode(500))
+    fun `preserves tmp file after all retries fail so next attempt can resume`() {
+        // Simulate every retry attempt failing mid-stream: server promises 16
+        // bytes via Content-Length but disconnects during the body. OkHttp
+        // throws, triggering retry. After all retries exhaust, we expect the
+        // .tmp file to persist (with whatever partial bytes made it to disk)
+        // so the worker can resume via Range: bytes=N- on a future invocation.
+        repeat(2) {
+            server.enqueue(
+                MockResponse()
+                    .setBody("ABCDEFGHIJKLMNOP")
+                    .setSocketPolicy(okhttp3.mockwebserver.SocketPolicy.DISCONNECT_DURING_RESPONSE_BODY)
+            )
+        }
 
         val dest = File(tmpDir.root, "model.onnx")
         try {
             downloadFile(server.url("/model.onnx").toString(), dest, maxRetries = 2)
         } catch (_: IOException) {}
 
-        assertFalse(dest.exists())
-        assertFalse(File(tmpDir.root, "model.onnx.tmp").exists())
+        assertFalse("final file should not exist on failure", dest.exists())
+        val tmp = File(tmpDir.root, "model.onnx.tmp")
+        assertTrue("partial .tmp should be preserved for resume", tmp.exists())
     }
 
     @Test