diff --git a/aconfig/Android.bp b/aconfig/Android.bp
index 8be93f0..768db02 100644
--- a/aconfig/Android.bp
+++ b/aconfig/Android.bp
@@ -6,7 +6,7 @@
 aconfig_declarations {
     name: "aconfig_settings_flags",
     package: "com.android.settings.flags",
-    container: "system",
+    container: "system_ext",
     srcs: [
         "*.aconfig",
         "catalyst/*.aconfig",
@@ -21,7 +21,7 @@
 aconfig_declarations {
     name: "factory_reset_flags",
     package: "com.android.settings.factory_reset",
-    container: "system",
+    container: "system_ext",
     srcs: ["factory_reset/*.aconfig"],
 }
 
@@ -33,7 +33,7 @@
 aconfig_declarations {
     name: "media_drm_flags",
     package: "com.android.settings.media_drm",
-    container: "system",
+    container: "system_ext",
     srcs: ["media_drm/*.aconfig"],
 }
 
@@ -45,7 +45,7 @@
 aconfig_declarations {
     name: "accessibility_flags",
     package: "com.android.settings.accessibility",
-    container: "system",
+    container: "system_ext",
     srcs: ["accessibility/*.aconfig"],
 }
 
@@ -57,7 +57,7 @@
 aconfig_declarations {
     name: "development_settings_flags",
     package: "com.android.settings.development",
-    container: "system",
+    container: "system_ext",
     srcs: [
         "development/**/*.aconfig",
     ],
@@ -71,7 +71,7 @@
 aconfig_declarations {
     name: "keyboard_flags",
     package: "com.android.settings.keyboard",
-    container: "system",
+    container: "system_ext",
     srcs: ["keyboard/*.aconfig"],
 }
 
diff --git a/aconfig/accessibility/accessibility_flags.aconfig b/aconfig/accessibility/accessibility_flags.aconfig
index 4a741a1..1871172 100644
--- a/aconfig/accessibility/accessibility_flags.aconfig
+++ b/aconfig/accessibility/accessibility_flags.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.accessibility"
-container: "system"
+container: "system_ext"
 
 # NOTE: Keep alphabetized to help limit merge conflicts from multiple simultaneous editors.
 
diff --git a/aconfig/catalyst/about_phone.aconfig b/aconfig/catalyst/about_phone.aconfig
index 5403b65..59a2228 100644
--- a/aconfig/catalyst/about_phone.aconfig
+++ b/aconfig/catalyst/about_phone.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "catalyst_legal_information"
diff --git a/aconfig/development/settings_core_flag_declarations.aconfig b/aconfig/development/settings_core_flag_declarations.aconfig
index b73b026..45768f4 100644
--- a/aconfig/development/settings_core_flag_declarations.aconfig
+++ b/aconfig/development/settings_core_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.development"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "deprecate_list_activity"
diff --git a/aconfig/factory_reset/factory_reset_flag_declarations.aconfig b/aconfig/factory_reset/factory_reset_flag_declarations.aconfig
index 7feebf5..dc7d8d4 100644
--- a/aconfig/factory_reset/factory_reset_flag_declarations.aconfig
+++ b/aconfig/factory_reset/factory_reset_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.factory_reset"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_factory_reset_wizard"
diff --git a/aconfig/keyboard/settings_physical_keyboard_a11y_features.aconfig b/aconfig/keyboard/settings_physical_keyboard_a11y_features.aconfig
index 00c0b18..ca5cb8d 100644
--- a/aconfig/keyboard/settings_physical_keyboard_a11y_features.aconfig
+++ b/aconfig/keyboard/settings_physical_keyboard_a11y_features.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.keyboard"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "keyboard_and_touchpad_a11y_new_page_enabled"
diff --git a/aconfig/media_drm/settings_mediadrm_flag_declarations.aconfig b/aconfig/media_drm/settings_mediadrm_flag_declarations.aconfig
index 3969b29..10579eb 100644
--- a/aconfig/media_drm/settings_mediadrm_flag_declarations.aconfig
+++ b/aconfig/media_drm/settings_mediadrm_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.media_drm"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "force_l3_enabled"
diff --git a/aconfig/settings_accessibility_flag_declarations_legacy.aconfig b/aconfig/settings_accessibility_flag_declarations_legacy.aconfig
index 6e02bfe..d0e5850 100644
--- a/aconfig/settings_accessibility_flag_declarations_legacy.aconfig
+++ b/aconfig/settings_accessibility_flag_declarations_legacy.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 # NOTE: Don't add new accessibility flags here, since the package name doesn't follow
 # the best practice for setting's feature flag go/settings-trunk-stable
diff --git a/aconfig/settings_biometrics_framework_flag_declarations.aconfig b/aconfig/settings_biometrics_framework_flag_declarations.aconfig
index 820786e..e81c68e 100644
--- a/aconfig/settings_biometrics_framework_flag_declarations.aconfig
+++ b/aconfig/settings_biometrics_framework_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "biometric_settings_provider"
diff --git a/aconfig/settings_biometrics_integration_declarations.aconfig b/aconfig/settings_biometrics_integration_declarations.aconfig
index ea3ac19..66d794b 100644
--- a/aconfig/settings_biometrics_integration_declarations.aconfig
+++ b/aconfig/settings_biometrics_integration_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "sfps_enroll_refinement"
diff --git a/aconfig/settings_bluetooth_declarations.aconfig b/aconfig/settings_bluetooth_declarations.aconfig
index 835a637..0c423b5 100644
--- a/aconfig/settings_bluetooth_declarations.aconfig
+++ b/aconfig/settings_bluetooth_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_offload_bluetooth_operations_to_background_thread"
diff --git a/aconfig/settings_connecteddevice_flag_declarations.aconfig b/aconfig/settings_connecteddevice_flag_declarations.aconfig
index 8720260..ee0c233 100644
--- a/aconfig/settings_connecteddevice_flag_declarations.aconfig
+++ b/aconfig/settings_connecteddevice_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "rotation_connected_display_setting"
diff --git a/aconfig/settings_contacts_default_account_flag_declarations.aconfig b/aconfig/settings_contacts_default_account_flag_declarations.aconfig
index eb877af..621714d 100644
--- a/aconfig/settings_contacts_default_account_flag_declarations.aconfig
+++ b/aconfig/settings_contacts_default_account_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_contacts_default_account_in_settings"
diff --git a/aconfig/settings_datetime_flag_declarations.aconfig b/aconfig/settings_datetime_flag_declarations.aconfig
index 3d9d8b3..dc3f1f4 100644
--- a/aconfig/settings_datetime_flag_declarations.aconfig
+++ b/aconfig/settings_datetime_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "datetime_feedback"
diff --git a/aconfig/settings_development_flag_declarations.aconfig b/aconfig/settings_development_flag_declarations.aconfig
index 318f862..b9a084f 100644
--- a/aconfig/settings_development_flag_declarations.aconfig
+++ b/aconfig/settings_development_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 # NOTE: Keep alphabetized to help limit merge conflicts from multiple simultaneous editors.
 
diff --git a/aconfig/settings_device_diagnostics_declarations.aconfig b/aconfig/settings_device_diagnostics_declarations.aconfig
index 7423f2b..90a12db 100644
--- a/aconfig/settings_device_diagnostics_declarations.aconfig
+++ b/aconfig/settings_device_diagnostics_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_device_diagnostics_in_settings"
diff --git a/aconfig/settings_display_flag_declarations.aconfig b/aconfig/settings_display_flag_declarations.aconfig
index 9fe587b..52b9603 100644
--- a/aconfig/settings_display_flag_declarations.aconfig
+++ b/aconfig/settings_display_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "protect_screen_timeout_with_auth"
diff --git a/aconfig/settings_experience_flag_declarations.aconfig b/aconfig/settings_experience_flag_declarations.aconfig
index 17d0059..d5caccf 100644
--- a/aconfig/settings_experience_flag_declarations.aconfig
+++ b/aconfig/settings_experience_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "new_apn_page_enabled"
diff --git a/aconfig/settings_flag_declarations.aconfig b/aconfig/settings_flag_declarations.aconfig
index a9c7bd5..37a8798 100644
--- a/aconfig/settings_flag_declarations.aconfig
+++ b/aconfig/settings_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "show_factory_reset_cancel_button"
diff --git a/aconfig/settings_globalintl_flag_declarations.aconfig b/aconfig/settings_globalintl_flag_declarations.aconfig
index 12a61294..2f046d0 100644
--- a/aconfig/settings_globalintl_flag_declarations.aconfig
+++ b/aconfig/settings_globalintl_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "terms_of_address_enabled"
diff --git a/aconfig/settings_notification_flag_declarations.aconfig b/aconfig/settings_notification_flag_declarations.aconfig
index bdb6573..f2ef428 100644
--- a/aconfig/settings_notification_flag_declarations.aconfig
+++ b/aconfig/settings_notification_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "dedupe_dnd_settings_channels"
diff --git a/aconfig/settings_onboarding_experience_flag_declarations.aconfig b/aconfig/settings_onboarding_experience_flag_declarations.aconfig
index 8d58d40..830c101 100644
--- a/aconfig/settings_onboarding_experience_flag_declarations.aconfig
+++ b/aconfig/settings_onboarding_experience_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_sound_backup"
diff --git a/aconfig/settings_perform_backup_tasks_flag_declarations.aconfig b/aconfig/settings_perform_backup_tasks_flag_declarations.aconfig
index 86bae9d..dcb876b 100644
--- a/aconfig/settings_perform_backup_tasks_flag_declarations.aconfig
+++ b/aconfig/settings_perform_backup_tasks_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_perform_backup_tasks_in_settings"
diff --git a/aconfig/settings_security_flag_declarations.aconfig b/aconfig/settings_security_flag_declarations.aconfig
index 3684212..e27f835 100644
--- a/aconfig/settings_security_flag_declarations.aconfig
+++ b/aconfig/settings_security_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "protect_lock_after_timeout_with_auth"
diff --git a/aconfig/settings_telephony_flag_declarations.aconfig b/aconfig/settings_telephony_flag_declarations.aconfig
index dab1b45..c12de7a 100644
--- a/aconfig/settings_telephony_flag_declarations.aconfig
+++ b/aconfig/settings_telephony_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "remove_key_hide_enable_2g"
diff --git a/aconfig/settings_threadnetwork_flag_declarations.aconfig b/aconfig/settings_threadnetwork_flag_declarations.aconfig
index e5448a9..9966467 100644
--- a/aconfig/settings_threadnetwork_flag_declarations.aconfig
+++ b/aconfig/settings_threadnetwork_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
     name: "thread_settings_enabled"
diff --git a/aconfig/settings_voice_activation_apps_flag_declarations.aconfig b/aconfig/settings_voice_activation_apps_flag_declarations.aconfig
index d72e67f..9ca3525 100644
--- a/aconfig/settings_voice_activation_apps_flag_declarations.aconfig
+++ b/aconfig/settings_voice_activation_apps_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 flag {
   name: "enable_voice_activation_apps_in_settings"
diff --git a/aconfig/settings_wifi_flag_declarations.aconfig b/aconfig/settings_wifi_flag_declarations.aconfig
index 67ed943..cb8007f 100644
--- a/aconfig/settings_wifi_flag_declarations.aconfig
+++ b/aconfig/settings_wifi_flag_declarations.aconfig
@@ -1,5 +1,5 @@
 package: "com.android.settings.flags"
-container: "system"
+container: "system_ext"
 
 # NOTE: Keep alphabetized to help limit merge conflicts from multiple simultaneous editors.
 
diff --git a/tests/Enable16KbTests/test_16kb_app/src/com/android/settings/development/test/Enable16KbDeviceTest.java b/tests/Enable16KbTests/test_16kb_app/src/com/android/settings/development/test/Enable16KbDeviceTest.java
index 9e489cf..ecb3123 100644
--- a/tests/Enable16KbTests/test_16kb_app/src/com/android/settings/development/test/Enable16KbDeviceTest.java
+++ b/tests/Enable16KbTests/test_16kb_app/src/com/android/settings/development/test/Enable16KbDeviceTest.java
@@ -37,6 +37,8 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
+import java.util.Locale;
+
 @RunWith(AndroidJUnit4.class)
 public class Enable16KbDeviceTest {
     private static final long TIMEOUT = 2000;
@@ -92,7 +94,15 @@
         // Verify that ext4 toggle is visible
         verifyTextOnScreen(EXT4_TITLE);
 
-        mDevice.wait(Until.findObject(By.text(EXT4_CONFIRMATION)), TIMEOUT).click();
+        UiObject2 confirmationObject =
+            mDevice.wait(Until.findObject(By.text(EXT4_CONFIRMATION)), TIMEOUT);
+        if (confirmationObject == null) {
+            // Workaround for (b/390535191). AOSP targets display the string in all caps.
+            confirmationObject = mDevice.wait(
+                Until.findObject(By.text(EXT4_CONFIRMATION.toUpperCase(Locale.ROOT))), TIMEOUT);
+        }
+        assertTrue(confirmationObject != null);
+        confirmationObject.click();
     }
 
     @Test