diff --git a/echolot-app/app/src/main/AndroidManifest.xml b/echolot-app/app/src/main/AndroidManifest.xml
index 0030503..a63d39f 100644
--- a/echolot-app/app/src/main/AndroidManifest.xml
+++ b/echolot-app/app/src/main/AndroidManifest.xml
@@ -21,6 +21,8 @@
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />
     <!-- Only so the relay's ongoing status is visible; the service runs either way. -->
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <!-- So the relay survives a reboot of a device left running it (see RelayBootReceiver). -->
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
 
     <application
         android:allowBackup="false"
@@ -73,6 +75,19 @@
             android:exported="false"
             android:foregroundServiceType="dataSync" />
 
+        <!--
+          Exported because the system delivers these broadcasts; the receiver itself starts
+          nothing unless the relay was already switched on in a debug build.
+        -->
+        <receiver
+            android:name=".RelayBootReceiver"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.BOOT_COMPLETED" />
+                <action android:name="android.intent.action.MY_PACKAGE_REPLACED" />
+            </intent-filter>
+        </receiver>
+
         <provider
             android:name="androidx.core.content.FileProvider"
             android:authorities="${applicationId}.fileprovider"
diff --git a/echolot-app/app/src/main/kotlin/app/echo_lot/app/AdbRelayService.kt b/echolot-app/app/src/main/kotlin/app/echo_lot/app/AdbRelayService.kt
index 5f2584d..bdf7cc3 100644
--- a/echolot-app/app/src/main/kotlin/app/echo_lot/app/AdbRelayService.kt
+++ b/echolot-app/app/src/main/kotlin/app/echo_lot/app/AdbRelayService.kt
@@ -56,6 +56,11 @@ class AdbRelayService : Service() {
         r.start()
 
         scope.launch {
+            // Poll quickly until the first endpoint has actually been reported, then settle into
+            // the heartbeat. Discovery takes a few seconds, so a loop that only ever waited the
+            // heartbeat would see nothing on its first pass and then sit silent for two minutes —
+            // exactly when someone has just switched the relay on and is watching for it to work.
+            var reportedOnce = false
             while (true) {
                 val ep = r.lastEndpoint
                 if (ep != null) {
@@ -66,13 +71,14 @@ class AdbRelayService : Service() {
                     val result = post(settings, ep)
                     status = if (result == null) {
                         lastPosted = wire
+                        reportedOnce = true
                         "reported $wire"
                     } else {
                         "found $wire, but reporting failed: $result"
                     }
                     notify(status)
                 }
-                delay(HEARTBEAT_MS)
+                delay(if (reportedOnce) HEARTBEAT_MS else STARTUP_POLL_MS)
             }
         }
     }
@@ -143,6 +149,9 @@ class AdbRelayService : Service() {
          */
         private const val HEARTBEAT_MS = 120_000L
 
+        /** Retry cadence before the first successful report; cheap, and only ever runs at start. */
+        private const val STARTUP_POLL_MS = 5_000L
+
         fun start(ctx: Context) {
             val i = Intent(ctx, AdbRelayService::class.java)
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) ctx.startForegroundService(i)
diff --git a/echolot-app/app/src/main/kotlin/app/echo_lot/app/RelayBootReceiver.kt b/echolot-app/app/src/main/kotlin/app/echo_lot/app/RelayBootReceiver.kt
new file mode 100644
index 0000000..bb6c582
--- /dev/null
+++ b/echolot-app/app/src/main/kotlin/app/echo_lot/app/RelayBootReceiver.kt
@@ -0,0 +1,33 @@
+// SPDX-FileCopyrightText: 2026 Echolot contributors
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package app.echo_lot.app
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+
+/**
+ * Brings the relay back after a reboot or an app update, without anyone opening the app.
+ *
+ * The relay's whole purpose is to keep answering "where is this device" while the device sits on a
+ * shelf unattended. Starting it only from [MainActivity] meant it silently did not come back from
+ * either event — and a relay that has quietly stopped is worse than one that was never switched
+ * on, because the endpoint it last published keeps looking authoritative while pointing at a port
+ * nothing is listening on.
+ *
+ * `MY_PACKAGE_REPLACED` matters as much as boot here: installing a new build is the single most
+ * common way this service dies during development, which is exactly when it is being relied on.
+ */
+class RelayBootReceiver : BroadcastReceiver() {
+    override fun onReceive(ctx: Context, intent: Intent) {
+        if (!BuildConfig.DEBUG) return
+        when (intent.action) {
+            Intent.ACTION_BOOT_COMPLETED, Intent.ACTION_MY_PACKAGE_REPLACED -> {
+                if (Settings(ctx).adbRelayEnabled) {
+                    runCatching { AdbRelayService.start(ctx) }
+                }
+            }
+        }
+    }
+}