diff --git a/packages/firmware_updater/lib/firmware_app.dart b/packages/firmware_updater/lib/firmware_app.dart
index 0d4c120f..68cfdb74 100644
--- a/packages/firmware_updater/lib/firmware_app.dart
+++ b/packages/firmware_updater/lib/firmware_app.dart
@@ -8,6 +8,7 @@ import 'package:firmware_updater/fwupd_mock_service.dart';
 import 'package:firmware_updater/fwupd_notifier.dart';
 import 'package:firmware_updater/widgets.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/scheduler.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:fwupd/fwupd.dart';
 import 'package:gtk/gtk.dart';
@@ -39,6 +40,7 @@ class FirmwareApp extends StatefulWidget {
 class _FirmwareAppState extends State<FirmwareApp> {
   YaruPageController? _controller;
   bool _initialized = false;
+  bool _onBattery = false;
 
   @override
   void initState() {
@@ -60,6 +62,36 @@ class _FirmwareAppState extends State<FirmwareApp> {
       });
     });
     gtkNotifier.addCommandLineListener(_commandLineListener);
+
+    SchedulerBinding.instance.addPostFrameCallback((_) async {
+      final l10n = AppLocalizations.of(context);
+      if (_onBattery) {
+        await _showAlertDialog(l10n.acPowerTitle, l10n.acPowerMustBeSupplied);
+      }
+    });
+  }
+
+  Future<dynamic> _showAlertDialog(String titleP, String contentP) {
+    return showDialog(
+      context: context,
+      builder: (context) {
+        final l10n = AppLocalizations.of(context);
+        // return object of type Dialog
+        return AlertDialog(
+          title: Text(titleP),
+          content: Text(contentP),
+          actions: <Widget>[
+            // usually buttons at the bottom of the dialog
+            TextButton(
+              child: Text(l10n.ok),
+              onPressed: () {
+                Navigator.of(context).pop();
+              },
+            ),
+          ],
+        );
+      },
+    );
   }
 
   @override
@@ -109,12 +141,10 @@ class _FirmwareAppState extends State<FirmwareApp> {
   Widget build(BuildContext context) {
     final store = context.watch<DeviceStore>();
     final l10n = AppLocalizations.of(context);
+    _onBattery =
+        context.select<FwupdNotifier, bool>((notifier) => notifier.onBattery);
     return _initialized
-        ? ErrorBanner(
-            message: context.select<FwupdNotifier, bool>(
-                    (notifier) => notifier.onBattery)
-                ? l10n.batteryWarning
-                : null,
+        ? Center(
             child: YaruMasterDetailPage(
               appBar: YaruWindowTitleBar(title: Text(l10n.appTitle)),
               controller: _controller,
diff --git a/packages/firmware_updater/lib/src/l10n/app_en.arb b/packages/firmware_updater/lib/src/l10n/app_en.arb
index 038e5d7e..1f43d200 100644
--- a/packages/firmware_updater/lib/src/l10n/app_en.arb
+++ b/packages/firmware_updater/lib/src/l10n/app_en.arb
@@ -147,5 +147,9 @@
   },
   "currentVersion": "Current Version",
   "minVersion": "Minimum Version",
-  "latestVersion": "Latest Version"
+  "latestVersion": "Latest Version",
+  "acPowerTitle": "You are currently on battery power",
+  "acPowerMustBeSupplied": "BIOS and other updates can't commence on battery power.\nPlug into A/C power and restart this app to perform those updates if available.",
+  "legacyBootTitle": "Legacy Boot Mode is selected in the BIOS",
+  "legacyBootCantUpdateInThisMode": "BIOS and other updates can't commence in this mode.\nSwitch to UEFI Boot Mode in the BIOS to proceed.\nNote - this may require an OS reinstall."
 }
\ No newline at end of file
diff --git a/packages/firmware_updater/lib/src/widgets/error_banner.dart b/packages/firmware_updater/lib/src/widgets/error_banner.dart
deleted file mode 100644
index b0a25b4a..00000000
--- a/packages/firmware_updater/lib/src/widgets/error_banner.dart
+++ /dev/null
@@ -1,59 +0,0 @@
-import 'package:flutter/material.dart';
-
-class ErrorBanner extends StatefulWidget {
-  const ErrorBanner({
-    required this.child,
-    this.message,
-    super.key,
-  });
-
-  final Widget child;
-  final String? message;
-
-  @override
-  State<ErrorBanner> createState() => _ErrorBannerState();
-}
-
-class _ErrorBannerState extends State<ErrorBanner> {
-  bool _visible = true;
-
-  @override
-  Widget build(BuildContext context) {
-    return Material(
-      child: Column(
-        crossAxisAlignment: CrossAxisAlignment.stretch,
-        children: [
-          if (widget.message != null && _visible)
-            Container(
-              color: Theme.of(context).colorScheme.errorContainer,
-              child: Row(
-                children: [
-                  Expanded(
-                    child: Text(
-                      widget.message!,
-                      style: Theme.of(context).textTheme.labelMedium!.copyWith(
-                            color:
-                                Theme.of(context).colorScheme.onErrorContainer,
-                          ),
-                      textAlign: TextAlign.center,
-                    ),
-                  ),
-                  IconButton(
-                    onPressed: () => setState(() => _visible = false),
-                    icon: const Icon(Icons.close, size: 16),
-                    padding: EdgeInsets.zero,
-                    visualDensity: const VisualDensity(
-                      horizontal: -4,
-                      vertical: -4,
-                    ),
-                    color: Theme.of(context).colorScheme.onErrorContainer,
-                  )
-                ],
-              ),
-            ),
-          Expanded(child: widget.child),
-        ],
-      ),
-    );
-  }
-}
diff --git a/packages/firmware_updater/lib/widgets.dart b/packages/firmware_updater/lib/widgets.dart
index 71cddb89..3c1f3380 100644
--- a/packages/firmware_updater/lib/widgets.dart
+++ b/packages/firmware_updater/lib/widgets.dart
@@ -3,7 +3,6 @@ export 'src/widgets/device_header.dart';
 export 'src/widgets/device_icon.dart';
 export 'src/widgets/device_panel_list.dart';
 export 'src/widgets/dialogs.dart';
-export 'src/widgets/error_banner.dart';
 export 'src/widgets/option_card.dart';
 export 'src/widgets/refresh_button.dart';
 export 'src/widgets/release_card.dart';
diff --git a/packages/firmware_updater/test/firmware_app_test.dart b/packages/firmware_updater/test/firmware_app_test.dart
index ca778829..50e715c9 100644
--- a/packages/firmware_updater/test/firmware_app_test.dart
+++ b/packages/firmware_updater/test/firmware_app_test.dart
@@ -140,12 +140,19 @@ void main() {
     registerMockService<FwupdDbusService>(mockService());
     registerMockService<GtkApplicationNotifier>(mockGtkApplicationNotifier());
 
+    // Check to make sure the AC-power warning dialog is displayed
     final store = mockStore(devices: devices);
     await tester.pumpApp((_) =>
         buildPage(store: store, notifier: mockNotifier(onBattery: true)));
     await tester.pumpAndSettle();
 
-    expect(find.text(tester.lang.batteryWarning), findsOneWidget);
+    expect(find.text(tester.lang.acPowerMustBeSupplied), findsOneWidget);
+
+    // Make sure the dialog is dismissed by pressing the "OK" button
+    // (The OK button is the only TextButton on the dialog)
+    await tester.tap(find.byType(TextButton));
+    await tester.pumpAndSettle();
+    expect(find.text(tester.lang.acPowerMustBeSupplied), findsNothing);
   });
 
   testWidgets('register callbacks', (tester) async {