diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/manage/BluetoothTethering.kt b/mobile/src/main/java/be/mygod/vpnhotspot/manage/BluetoothTethering.kt
index c2dc3d5b..c8eea2ca 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/manage/BluetoothTethering.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/manage/BluetoothTethering.kt
@@ -35,7 +35,7 @@ class BluetoothTethering(context: Context, val stateListener: (Int) -> Unit) :
                 app.registerReceiver(receiver, IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED))
         private val Intent.bluetoothState get() = getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR)
 
-        private var pendingCallback: TetheringManager.OnStartTetheringCallback? = null
+        private var pendingCallback: TetheringManager.StartTetheringCallback? = null
 
         /**
          * https://android.googlesource.com/platform/packages/apps/Settings/+/b1af85d/src/com/android/settings/TetherSettings.java#215
@@ -72,7 +72,7 @@ class BluetoothTethering(context: Context, val stateListener: (Int) -> Unit) :
          * https://android.googlesource.com/platform/packages/apps/Settings/+/b1af85d/src/com/android/settings/TetherSettings.java#384
          */
         @RequiresApi(24)
-        fun start(callback: TetheringManager.OnStartTetheringCallback) {
+        fun start(callback: TetheringManager.StartTetheringCallback) {
             if (pendingCallback != null) return
             val adapter = BluetoothAdapter.getDefaultAdapter()
             if (adapter?.state == BluetoothAdapter.STATE_OFF) {
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt
index 853953f4..215aa0a4 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt
@@ -7,7 +7,6 @@ import android.view.View
 import android.widget.Toast
 import androidx.annotation.RequiresApi
 import androidx.core.net.toUri
-import androidx.core.os.BuildCompat
 import androidx.core.view.updatePaddingRelative
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
@@ -20,12 +19,13 @@ import be.mygod.vpnhotspot.net.TetherType
 import be.mygod.vpnhotspot.net.TetheringManager
 import be.mygod.vpnhotspot.net.wifi.WifiApManager
 import be.mygod.vpnhotspot.util.readableMessage
+import be.mygod.vpnhotspot.widget.SmartSnackbar
 import timber.log.Timber
 import java.io.IOException
 import java.lang.reflect.InvocationTargetException
 
 sealed class TetherManager(protected val parent: TetheringFragment) : Manager(),
-        TetheringManager.OnStartTetheringCallback {
+        TetheringManager.StartTetheringCallback {
     class ViewHolder(private val binding: ListitemInterfaceBinding) : RecyclerView.ViewHolder(binding.root),
             View.OnClickListener {
         init {
@@ -91,8 +91,9 @@ sealed class TetherManager(protected val parent: TetheringFragment) : Manager(),
     protected abstract fun stop()
 
     override fun onTetheringStarted() = data.notifyChange()
-    override fun onTetheringFailed() {
-        Timber.d(javaClass.simpleName, "onTetheringFailed")
+    override fun onTetheringFailed(error: Int?) {
+        Timber.d(javaClass.simpleName, "onTetheringFailed: $error")
+        error?.let { SmartSnackbar.make("$tetherType: ${TetheringManager.tetherErrorMessage(it)}") }
         data.notifyChange()
     }
 
@@ -101,34 +102,12 @@ sealed class TetherManager(protected val parent: TetheringFragment) : Manager(),
     }
 
     private fun getErrorMessage(iface: String): String {
-        val error = try {
+        return TetheringManager.tetherErrorMessage(try {
             TetheringManager.getLastTetherError(iface)
         } catch (e: InvocationTargetException) {
             if (Build.VERSION.SDK_INT !in 24..25 || e.cause !is SecurityException) Timber.w(e) else Timber.d(e)
             return e.readableMessage
-        }
-        if (BuildCompat.isAtLeastR()) try {
-            TetheringManager.tetherErrors.get(error)?.let { return it }
-        } catch (e: ReflectiveOperationException) {
-            Timber.w(e)
-        }
-        return when (error) {
-            TetheringManager.TETHER_ERROR_NO_ERROR -> "TETHER_ERROR_NO_ERROR"
-            TetheringManager.TETHER_ERROR_UNKNOWN_IFACE -> "TETHER_ERROR_UNKNOWN_IFACE"
-            TetheringManager.TETHER_ERROR_SERVICE_UNAVAIL -> "TETHER_ERROR_SERVICE_UNAVAIL"
-            TetheringManager.TETHER_ERROR_UNSUPPORTED -> "TETHER_ERROR_UNSUPPORTED"
-            TetheringManager.TETHER_ERROR_UNAVAIL_IFACE -> "TETHER_ERROR_UNAVAIL_IFACE"
-            TetheringManager.TETHER_ERROR_MASTER_ERROR -> "TETHER_ERROR_MASTER_ERROR"
-            TetheringManager.TETHER_ERROR_TETHER_IFACE_ERROR -> "TETHER_ERROR_TETHER_IFACE_ERROR"
-            TetheringManager.TETHER_ERROR_UNTETHER_IFACE_ERROR -> "TETHER_ERROR_UNTETHER_IFACE_ERROR"
-            TetheringManager.TETHER_ERROR_ENABLE_NAT_ERROR -> "TETHER_ERROR_ENABLE_NAT_ERROR"
-            TetheringManager.TETHER_ERROR_DISABLE_NAT_ERROR -> "TETHER_ERROR_DISABLE_NAT_ERROR"
-            TetheringManager.TETHER_ERROR_IFACE_CFG_ERROR -> "TETHER_ERROR_IFACE_CFG_ERROR"
-            TetheringManager.TETHER_ERROR_PROVISION_FAILED -> "TETHER_ERROR_PROVISION_FAILED"
-            TetheringManager.TETHER_ERROR_DHCPSERVER_ERROR -> "TETHER_ERROR_DHCPSERVER_ERROR"
-            TetheringManager.TETHER_ERROR_ENTITLEMENT_UNKNOWN -> "TETHER_ERROR_ENTITLEMENT_UNKNOWN"
-            else -> app.getString(R.string.failure_reason_unknown, error)
-        }
+        })
     }
     fun updateErrorMessage(errored: List<String>) {
         data.text = errored.filter { TetherType.ofInterface(it) == tetherType }
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringTileService.kt b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringTileService.kt
index e8f8a68a..48bc1f9f 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringTileService.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringTileService.kt
@@ -21,7 +21,7 @@ import java.io.IOException
 import java.lang.reflect.InvocationTargetException
 
 @RequiresApi(24)
-sealed class TetheringTileService : TetherListeningTileService(), TetheringManager.OnStartTetheringCallback {
+sealed class TetheringTileService : TetherListeningTileService(), TetheringManager.StartTetheringCallback {
     protected val tileOff by lazy { Icon.createWithResource(application, icon) }
     protected val tileOn by lazy { Icon.createWithResource(application, R.drawable.ic_quick_settings_tile_on) }
 
@@ -108,8 +108,9 @@ sealed class TetheringTileService : TetherListeningTileService(), TetheringManag
     }
 
     override fun onTetheringStarted() = updateTile()
-    override fun onTetheringFailed() {
-        Timber.d("onTetheringFailed")
+    override fun onTetheringFailed(error: Int?) {
+        Timber.d("onTetheringFailed: $error")
+        error?.let { Toast.makeText(this, TetheringManager.tetherErrorMessage(it), Toast.LENGTH_LONG).show() }
         updateTile()
     }
 
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/TetheringManager.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/TetheringManager.kt
index b4e55325..7936c7ac 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/TetheringManager.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/TetheringManager.kt
@@ -1,16 +1,21 @@
 package be.mygod.vpnhotspot.net
 
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.net.ConnectivityManager
+import android.net.LinkAddress
 import android.os.Build
 import android.os.Handler
 import androidx.annotation.RequiresApi
 import androidx.collection.SparseArrayCompat
 import androidx.core.os.BuildCompat
 import be.mygod.vpnhotspot.App.Companion.app
+import be.mygod.vpnhotspot.R
 import com.android.dx.stock.ProxyBuilder
 import timber.log.Timber
 import java.lang.ref.WeakReference
+import java.lang.reflect.InvocationTargetException
+import java.util.concurrent.Executor
 
 /**
  * Heavily based on:
@@ -21,7 +26,7 @@ object TetheringManager {
     /**
      * Callback for use with [startTethering] to find out whether tethering succeeded.
      */
-    interface OnStartTetheringCallback {
+    interface StartTetheringCallback {
         /**
          * Called when tethering has been successfully started.
          */
@@ -29,12 +34,22 @@ object TetheringManager {
 
         /**
          * Called when starting tethering failed.
+         *
+         * @param error The error that caused the failure.
          */
-        fun onTetheringFailed() { }
+        fun onTetheringFailed(error: Int? = null) { }
 
         fun onException() { }
     }
 
+    /**
+     * Use with {@link #getSystemService(String)} to retrieve a {@link android.net.TetheringManager}
+     * for managing tethering functions.
+     * @hide
+     * @see android.net.TetheringManager
+     */
+    const val TETHERING_SERVICE = "tethering"
+
     /**
      * This is a sticky broadcast since almost forever.
      *
@@ -62,59 +77,95 @@ object TetheringManager {
      * for any interfaces listed here.
      */
     const val EXTRA_ERRORED_TETHER = "erroredArray"
-    const val TETHER_ERROR_NO_ERROR             = 0
-    const val TETHER_ERROR_UNKNOWN_IFACE        = 1
-    const val TETHER_ERROR_SERVICE_UNAVAIL      = 2
-    const val TETHER_ERROR_UNSUPPORTED          = 3
-    const val TETHER_ERROR_UNAVAIL_IFACE        = 4
-    const val TETHER_ERROR_MASTER_ERROR         = 5
-    const val TETHER_ERROR_TETHER_IFACE_ERROR   = 6
-    const val TETHER_ERROR_UNTETHER_IFACE_ERROR = 7
-    const val TETHER_ERROR_ENABLE_NAT_ERROR     = 8
-    const val TETHER_ERROR_DISABLE_NAT_ERROR    = 9
-    const val TETHER_ERROR_IFACE_CFG_ERROR      = 10
-    const val TETHER_ERROR_PROVISION_FAILED     = 11
-    const val TETHER_ERROR_DHCPSERVER_ERROR     = 12
-    const val TETHER_ERROR_ENTITLEMENT_UNKNOWN  = 13
 
+    // tether errors defined in ConnectivityManager up to Android 10
+    private const val TETHER_ERROR_NO_ERROR             = 0
+    private const val TETHER_ERROR_UNKNOWN_IFACE        = 1
+    private const val TETHER_ERROR_SERVICE_UNAVAIL      = 2
+    private const val TETHER_ERROR_UNSUPPORTED          = 3
+    private const val TETHER_ERROR_UNAVAIL_IFACE        = 4
+    private const val TETHER_ERROR_MASTER_ERROR         = 5
+    private const val TETHER_ERROR_TETHER_IFACE_ERROR   = 6
+    private const val TETHER_ERROR_UNTETHER_IFACE_ERROR = 7
+    private const val TETHER_ERROR_ENABLE_NAT_ERROR     = 8
+    private const val TETHER_ERROR_DISABLE_NAT_ERROR    = 9
+    private const val TETHER_ERROR_IFACE_CFG_ERROR      = 10
+    private const val TETHER_ERROR_PROVISION_FAILED     = 11
+    private const val TETHER_ERROR_DHCPSERVER_ERROR     = 12
+    private const val TETHER_ERROR_ENTITLEMENT_UNKNOWN  = 13
+
+    @RequiresApi(24)
     const val TETHERING_WIFI = 0
     /**
      * Requires MANAGE_USB permission, unfortunately.
      *
      * Source: https://android.googlesource.com/platform/frameworks/base/+/7ca5d3a/services/usb/java/com/android/server/usb/UsbService.java#389
      */
+    @RequiresApi(24)
     const val TETHERING_USB = 1
     /**
      * Requires BLUETOOTH permission, or BLUETOOTH_PRIVILEGED on API 30+.
      */
+    @RequiresApi(24)
     const val TETHERING_BLUETOOTH = 2
 
     @get:RequiresApi(30)
-    val tetherErrors by lazy {
-        SparseArrayCompat<String>().apply {
-            for (field in Class.forName("android.net.TetheringManager").declaredFields) try {
-                // all TETHER_ERROR_* are system-api since API 30
-                if (field.name.startsWith("TETHER_ERROR_")) put(field.get(null) as Int, field.name)
-            } catch (e: Exception) {
-                Timber.w(e)
-            }
-        }
-    }
+    private val clazz by lazy { Class.forName("android.net.TetheringManager") }
+    @get:RequiresApi(30)
+    private val instance by lazy { app.getSystemService(TETHERING_SERVICE) }
 
+    @get:RequiresApi(24)
     private val classOnStartTetheringCallback by lazy {
         Class.forName("android.net.ConnectivityManager\$OnStartTetheringCallback")
     }
-    private val startTethering by lazy {
+    @get:RequiresApi(24)
+    private val startTetheringLegacy by lazy {
         ConnectivityManager::class.java.getDeclaredMethod("startTethering",
                 Int::class.java, Boolean::class.java, classOnStartTetheringCallback, Handler::class.java)
     }
-    private val stopTethering by lazy {
+    @get:RequiresApi(24)
+    private val stopTetheringLegacy by lazy {
         ConnectivityManager::class.java.getDeclaredMethod("stopTethering", Int::class.java)
     }
+    @get:RequiresApi(24)
     private val getLastTetherError by lazy {
         ConnectivityManager::class.java.getDeclaredMethod("getLastTetherError", String::class.java)
     }
 
+    @get:RequiresApi(30)
+    private val classTetheringRequestBuilder by lazy {
+        Class.forName("android.net.TetheringManager\$TetheringRequest\$Builder")
+    }
+    @get:RequiresApi(30)
+    private val newTetheringRequestBuilder by lazy { classTetheringRequestBuilder.getConstructor(Int::class.java) }
+    @get:RequiresApi(30)
+    private val setStaticIpv4Addresses by lazy {
+        classTetheringRequestBuilder.getDeclaredMethod("setStaticIpv4Addresses",
+                LinkAddress::class.java, LinkAddress::class.java)
+    }
+    @get:RequiresApi(30)
+    private val setExemptFromEntitlementCheck by lazy {
+        classTetheringRequestBuilder.getDeclaredMethod("setExemptFromEntitlementCheck", Boolean::class.java)
+    }
+    @get:RequiresApi(30)
+    private val setShouldShowEntitlementUi by lazy {
+        classTetheringRequestBuilder.getDeclaredMethod("setShouldShowEntitlementUi", Boolean::class.java)
+    }
+    @get:RequiresApi(30)
+    private val build by lazy { classTetheringRequestBuilder.getDeclaredMethod("build") }
+
+    @get:RequiresApi(30)
+    private val classStartTetheringCallback by lazy {
+        Class.forName("android.net.TetheringManager\$StartTetheringCallback")
+    }
+    @get:RequiresApi(30)
+    private val startTethering by lazy {
+        clazz.getDeclaredMethod("startTethering", Class.forName("android.net.TetheringManager\$TetheringRequest"),
+                Executor::class.java, classStartTetheringCallback)
+    }
+    @get:RequiresApi(30)
+    private val stopTethering by lazy { clazz.getDeclaredMethod("stopTethering", Int::class.java) }
+
     /**
      * Runs tether provisioning for the given type if needed and then starts tethering if
      * the check succeeds. If no carrier provisioning is required for tethering, tethering is
@@ -131,24 +182,47 @@ object TetheringManager {
      *         check failing and how they can sign up for tethering if possible.
      * @param callback an {@link OnStartTetheringCallback} which will be called to notify the caller
      *         of the result of trying to tether.
-     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked
+     * @param address A pair (localIPv4Address, clientAddress) for API 30+. If present, it
+     *         configures tethering with static IPv4 assignment.
+     *
+     *         A DHCP server will be started, but will only be able to offer the client address.
+     *         The two addresses must be in the same prefix.
+     *
+     *         localIPv4Address: The preferred local IPv4 link address to use.
+     *         clientAddress: The static client address.
+     * @see setStaticIpv4Addresses
      */
     @RequiresApi(24)
-    fun startTethering(type: Int, showProvisioningUi: Boolean, callback: OnStartTetheringCallback,
-                       handler: Handler? = null) {
+    fun startTethering(type: Int, showProvisioningUi: Boolean, callback: StartTetheringCallback,
+                       handler: Handler? = null, address: Pair<LinkAddress, LinkAddress>? = null) {
         val reference = WeakReference(callback)
-        val proxy = ProxyBuilder.forClass(classOnStartTetheringCallback)
-                .dexCache(app.deviceStorage.cacheDir)
-                .handler { proxy, method, args ->
-                    if (args.isNotEmpty()) Timber.w("Unexpected args for ${method.name}: $args")
+        if (BuildCompat.isAtLeastR()) try {
+            val request = newTetheringRequestBuilder.newInstance(type).let { builder ->
+                // setting exemption requires TETHER_PRIVILEGED permission
+                if (app.checkSelfPermission("android.permission.TETHER_PRIVILEGED") ==
+                        PackageManager.PERMISSION_GRANTED) setExemptFromEntitlementCheck.invoke(builder, true)
+                setShouldShowEntitlementUi.invoke(builder, showProvisioningUi)
+                if (address != null) {
+                    val (localIPv4Address, clientAddress) = address
+                    setStaticIpv4Addresses(builder, localIPv4Address, clientAddress)
+                }
+                build.invoke(this)
+            }
+            val executor = Executor { if (handler == null) it.run() else handler.post(it) }
+            val proxy = ProxyBuilder.forClass(classStartTetheringCallback).apply {
+                dexCache(app.deviceStorage.cacheDir)
+                handler { proxy, method, args ->
                     @Suppress("NAME_SHADOWING") val callback = reference.get()
-                    when (method.name) {
+                    when (val name = method.name) {
                         "onTetheringStarted" -> {
+                            if (args.isNotEmpty()) Timber.w("Unexpected args for $name: $args")
                             callback?.onTetheringStarted()
                             null
                         }
                         "onTetheringFailed" -> {
-                            callback?.onTetheringFailed()
+                            if (args.size != 1) Timber.w("Unexpected args for $name: $args")
+                            callback?.onTetheringFailed(args.getOrNull(0) as? Int?)
                             null
                         }
                         else -> {
@@ -157,8 +231,34 @@ object TetheringManager {
                         }
                     }
                 }
-                .build()
-        startTethering.invoke(app.connectivity, type, showProvisioningUi, proxy, handler)
+            }.build()
+            startTethering.invoke(instance, request, executor, proxy)
+            return
+        } catch (e: InvocationTargetException) {
+            Timber.w(e, "Unable to invoke TetheringManager.startTethering, falling back to ConnectivityManager")
+        }
+        val proxy = ProxyBuilder.forClass(classOnStartTetheringCallback).apply {
+            dexCache(app.deviceStorage.cacheDir)
+            handler { proxy, method, args ->
+                if (args.isNotEmpty()) Timber.w("Unexpected args for ${method.name}: $args")
+                @Suppress("NAME_SHADOWING") val callback = reference.get()
+                when (method.name) {
+                    "onTetheringStarted" -> {
+                        callback?.onTetheringStarted()
+                        null
+                    }
+                    "onTetheringFailed" -> {
+                        callback?.onTetheringFailed()
+                        null
+                    }
+                    else -> {
+                        Timber.w("Unexpected method, calling super: $method")
+                        ProxyBuilder.callSuper(proxy, method, args)
+                    }
+                }
+            }
+        }.build()
+        startTetheringLegacy.invoke(app.connectivity, type, showProvisioningUi, proxy, handler)
     }
 
     /**
@@ -172,7 +272,12 @@ object TetheringManager {
      */
     @RequiresApi(24)
     fun stopTethering(type: Int) {
-        stopTethering.invoke(app.connectivity, type)
+        if (BuildCompat.isAtLeastR()) try {
+            stopTethering.invoke(instance, type)
+        } catch (e: InvocationTargetException) {
+            Timber.w(e, "Unable to invoke TetheringManager.stopTethering, falling back to ConnectivityManager")
+        }
+        stopTetheringLegacy.invoke(app.connectivity, type)
     }
 
     /**
@@ -185,6 +290,42 @@ object TetheringManager {
      */
     fun getLastTetherError(iface: String): Int = getLastTetherError.invoke(app.connectivity, iface) as Int
 
+    @get:RequiresApi(30)
+    private val tetherErrors by lazy {
+        SparseArrayCompat<String>().apply {
+            for (field in clazz.declaredFields) try {
+                // all TETHER_ERROR_* are system-api since API 30
+                if (field.name.startsWith("TETHER_ERROR_")) put(field.get(null) as Int, field.name)
+            } catch (e: Exception) {
+                Timber.w(e)
+            }
+        }
+    }
+    fun tetherErrorMessage(error: Int): String {
+        if (BuildCompat.isAtLeastR()) try {
+            tetherErrors.get(error)?.let { return it }
+        } catch (e: ReflectiveOperationException) {
+            Timber.w(e)
+        }
+        return when (error) {
+            TETHER_ERROR_NO_ERROR -> "TETHER_ERROR_NO_ERROR"
+            TETHER_ERROR_UNKNOWN_IFACE -> "TETHER_ERROR_UNKNOWN_IFACE"
+            TETHER_ERROR_SERVICE_UNAVAIL -> "TETHER_ERROR_SERVICE_UNAVAIL"
+            TETHER_ERROR_UNSUPPORTED -> "TETHER_ERROR_UNSUPPORTED"
+            TETHER_ERROR_UNAVAIL_IFACE -> "TETHER_ERROR_UNAVAIL_IFACE"
+            TETHER_ERROR_MASTER_ERROR -> "TETHER_ERROR_MASTER_ERROR"
+            TETHER_ERROR_TETHER_IFACE_ERROR -> "TETHER_ERROR_TETHER_IFACE_ERROR"
+            TETHER_ERROR_UNTETHER_IFACE_ERROR -> "TETHER_ERROR_UNTETHER_IFACE_ERROR"
+            TETHER_ERROR_ENABLE_NAT_ERROR -> "TETHER_ERROR_ENABLE_NAT_ERROR"
+            TETHER_ERROR_DISABLE_NAT_ERROR -> "TETHER_ERROR_DISABLE_NAT_ERROR"
+            TETHER_ERROR_IFACE_CFG_ERROR -> "TETHER_ERROR_IFACE_CFG_ERROR"
+            TETHER_ERROR_PROVISION_FAILED -> "TETHER_ERROR_PROVISION_FAILED"
+            TETHER_ERROR_DHCPSERVER_ERROR -> "TETHER_ERROR_DHCPSERVER_ERROR"
+            TETHER_ERROR_ENTITLEMENT_UNKNOWN -> "TETHER_ERROR_ENTITLEMENT_UNKNOWN"
+            else -> app.getString(R.string.failure_reason_unknown, error)
+        }
+    }
+
     val Intent.tetheredIfaces get() = getStringArrayListExtra(
             if (Build.VERSION.SDK_INT >= 26) EXTRA_ACTIVE_TETHER else EXTRA_ACTIVE_TETHER_LEGACY)
     val Intent.localOnlyTetheredIfaces get() = if (Build.VERSION.SDK_INT >= 26) {