diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index 9cb3dd6e4c0af..2ace0a211dd67 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -6343,6 +6343,7 @@ public class DevicePolicyManager {
      * The settings that can be updated by a profile or device owner with this method are:
      * <ul>
      * <li>{@link Settings.Secure#DEFAULT_INPUT_METHOD}</li>
+     * <li>{@link Settings.Secure#INSTALL_NON_MARKET_APPS}</li>
      * <li>{@link Settings.Secure#SKIP_FIRST_USE_HINTS}</li>
      * </ul>
      * <p>
@@ -6351,15 +6352,6 @@ public class DevicePolicyManager {
      * <li>{@link Settings.Secure#LOCATION_MODE}</li>
      * </ul>
      *
-     * <strong>Note: Starting from Android O, apps should no longer call this method with the
-     * setting {@link android.provider.Settings.Secure#INSTALL_NON_MARKET_APPS}, which is
-     * deprecated. Instead, device owners or profile owners should use the restriction
-     * {@link UserManager#DISALLOW_INSTALL_UNKNOWN_SOURCES}.
-     * If any app targeting {@link android.os.Build.VERSION_CODES#O} or higher calls this method
-     * with {@link android.provider.Settings.Secure#INSTALL_NON_MARKET_APPS},
-     * an {@link UnsupportedOperationException} is thrown.
-     * </strong>
-     *
      * @param admin Which {@link DeviceAdminReceiver} this request is associated with.
      * @param setting The name of the setting to update.
      * @param value The value to update the setting to.
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 7c8e264fe4422..c9b1c9cf27033 100755
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -5216,18 +5216,6 @@ public final class Settings {
          */
         public static final String INSTALL_NON_MARKET_APPS = "install_non_market_apps";
 
-        /**
-         * A flag to tell {@link com.android.server.devicepolicy.DevicePolicyManagerService} that
-         * the default for {@link #INSTALL_NON_MARKET_APPS} is reversed for this user on OTA. So it
-         * can set the restriction {@link android.os.UserManager#DISALLOW_INSTALL_UNKNOWN_SOURCES}
-         * on behalf of the profile owner if needed to make the change transparent for profile
-         * owners.
-         *
-         * @hide
-         */
-        public static final String UNKNOWN_SOURCES_DEFAULT_REVERSED =
-                "unknown_sources_default_reversed";
-
         /**
          * Comma-separated list of location providers that activities may access. Do not rely on
          * this value being present in settings.db or on ContentObserver notifications on the
diff --git a/packages/SettingsProvider/res/values/defaults.xml b/packages/SettingsProvider/res/values/defaults.xml
index 720612726a8f5..136f17e5a77c4 100644
--- a/packages/SettingsProvider/res/values/defaults.xml
+++ b/packages/SettingsProvider/res/values/defaults.xml
@@ -38,7 +38,7 @@
 
     <bool name="def_bluetooth_on">true</bool>
     <bool name="def_wifi_display_on">false</bool>
-    <bool name="def_install_non_market_apps">false</bool>
+    <bool name="def_install_non_market_apps">true</bool>
     <bool name="def_package_verifier_enable">true</bool>
     <!-- Comma-separated list of location providers.
          Network location is off by default because it requires
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
index ba657e963f3f9..88fc9cf68a43a 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
@@ -3174,17 +3174,9 @@ public class SettingsProvider extends ContentProvider {
                     // setting through the UI.
                     final SettingsState secureSetting = getSecureSettingsLocked(userId);
                     if (!mUserManager.hasUserRestriction(
-                            UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES, UserHandle.of(userId))
-                            && secureSetting.getSettingLocked(
-                            Settings.Secure.INSTALL_NON_MARKET_APPS).getValue().equals("0")) {
-
+                            UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES, UserHandle.of(userId))) {
                         secureSetting.insertSettingLocked(Settings.Secure.INSTALL_NON_MARKET_APPS,
                                 "1", null, true, SettingsState.SYSTEM_PACKAGE_NAME);
-                        // For managed profiles with profile owners, DevicePolicyManagerService
-                        // may want to set the user restriction in this case
-                        secureSetting.insertSettingLocked(
-                                Settings.Secure.UNKNOWN_SOURCES_DEFAULT_REVERSED, "1", null, true,
-                                SettingsState.SYSTEM_PACKAGE_NAME);
                     }
                     currentVersion = 138;
                 }
diff --git a/packages/SettingsProvider/test/src/com/android/providers/settings/InstallNonMarketAppsDeprecationTest.java b/packages/SettingsProvider/test/src/com/android/providers/settings/InstallNonMarketAppsDeprecationTest.java
index 2dbe14200a19c..51e43738b5376 100644
--- a/packages/SettingsProvider/test/src/com/android/providers/settings/InstallNonMarketAppsDeprecationTest.java
+++ b/packages/SettingsProvider/test/src/com/android/providers/settings/InstallNonMarketAppsDeprecationTest.java
@@ -22,7 +22,6 @@ import static junit.framework.Assert.assertTrue;
 
 import android.content.Context;
 import android.content.pm.UserInfo;
-import android.os.Process;
 import android.os.SystemClock;
 import android.os.UserManager;
 import android.provider.Settings;
@@ -48,7 +47,6 @@ public class InstallNonMarketAppsDeprecationTest extends BaseSettingsProviderTes
 
     private UserManager mUm;
     private boolean mHasUserRestriction;
-    private boolean mSystemSetUserRestriction;
     private List<UserInfo> mCurrentUsers;
 
     private String waitTillValueChanges(String errorMessage, String oldValue) {
@@ -86,9 +84,6 @@ public class InstallNonMarketAppsDeprecationTest extends BaseSettingsProviderTes
     public void setUp() {
         mUm = (UserManager) getContext().getSystemService(Context.USER_SERVICE);
         mHasUserRestriction = mUm.hasUserRestriction(UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES);
-        mSystemSetUserRestriction = mUm.getUserRestrictionSource(
-                UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES, Process.myUserHandle())
-                == UserManager.RESTRICTION_SOURCE_SYSTEM;
         mCurrentUsers = mUm.getUsers();
     }
 
@@ -122,13 +117,6 @@ public class InstallNonMarketAppsDeprecationTest extends BaseSettingsProviderTes
         String value = getSetting(SETTING_TYPE_SECURE, Settings.Secure.INSTALL_NON_MARKET_APPS);
         assertEquals(value, mHasUserRestriction ? "0" : "1");
 
-        if (mHasUserRestriction && !mSystemSetUserRestriction) {
-            // User restriction set by device policy. This case should be covered in DO/PO related
-            // tests. Pass.
-            Log.w(TAG, "User restriction set by PO/DO. Skipping testValueRespectsUserRestriction");
-            return;
-        }
-
         mUm.setUserRestriction(UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES, !mHasUserRestriction);
         value = waitTillValueChanges(
                 "Changing user restriction did not change the value of install_non_market_apps",
@@ -144,8 +132,8 @@ public class InstallNonMarketAppsDeprecationTest extends BaseSettingsProviderTes
 
     @After
     public void tearDown() {
-        if (!mHasUserRestriction || mSystemSetUserRestriction) {
-            // The test may have modified the user restriction state. Restore it.
+        if (mUm.hasUserRestriction(UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES)
+                != mHasUserRestriction) {
             mUm.setUserRestriction(UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES,
                     mHasUserRestriction);
         }
diff --git a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
index ff732edd9fb59..14b1741346b9b 100644
--- a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
+++ b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
@@ -194,7 +194,6 @@ import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
 import java.text.DateFormat;
-import java.text.NumberFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -2912,41 +2911,11 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         }
     }
 
-    private void ensureUnknownSourcesRestrictionForProfileOwners() {
-        synchronized (this) {
-            for (int userId : mOwners.getProfileOwnerKeys()) {
-                if (!mUserManager.isManagedProfile(userId) ||
-                        Settings.Secure.getIntForUser(mContext.getContentResolver(),
-                        Settings.Secure.UNKNOWN_SOURCES_DEFAULT_REVERSED, 0, userId) == 0) {
-                    continue;
-                }
-                setUserRestrictionOnBehalfOfProfileOwnerLocked(
-                        UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES, userId);
-                Settings.Secure.putIntForUser(mContext.getContentResolver(),
-                        Settings.Secure.UNKNOWN_SOURCES_DEFAULT_REVERSED, 0, userId);
-            }
-        }
-    }
-
-    private void setUserRestrictionOnBehalfOfProfileOwnerLocked(String userRestrictionKey,
-            int userId) {
-        if (UserRestrictionsUtils.isValidRestriction(userRestrictionKey) &&
-                UserRestrictionsUtils.canProfileOwnerChange(userRestrictionKey, userId)) {
-            ActiveAdmin profileOwner = getProfileOwnerAdminLocked(userId);
-            if (profileOwner == null) {
-                return;
-            }
-            Bundle restrictions = profileOwner.ensureUserRestrictions();
-            restrictions.putBoolean(userRestrictionKey, true);
-            saveUserRestrictionsLocked(userId);
-        }
-    }
-
     private void onLockSettingsReady() {
         getUserData(UserHandle.USER_SYSTEM);
         loadOwners();
         cleanUpOldUsers();
-        ensureUnknownSourcesRestrictionForProfileOwners();
+
         onStartUser(UserHandle.USER_SYSTEM);
 
         // Register an observer for watching for user setup complete and settings changes.
@@ -6669,12 +6638,6 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
             mOwners.writeProfileOwner(userHandle);
             Slog.i(LOG_TAG, "Profile owner set: " + who + " on user " + userHandle);
 
-            if (mUserManager.isManagedProfile(userHandle)) {
-                setUserRestrictionOnBehalfOfProfileOwnerLocked(
-                        UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES, userHandle);
-                Settings.Secure.putIntForUser(mContext.getContentResolver(),
-                        Settings.Secure.UNKNOWN_SOURCES_DEFAULT_REVERSED, 0, userHandle);
-            }
             return true;
         }
     }
@@ -8761,27 +8724,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
                 throw new SecurityException(String.format(
                         "Permission denial: Profile owners cannot update %1$s", setting));
             }
-            if (setting.equals(Settings.Secure.INSTALL_NON_MARKET_APPS)) {
-                if (getTargetSdk(who.getPackageName(), callingUserId) >= Build.VERSION_CODES.O) {
-                    throw new UnsupportedOperationException(Settings.Secure.INSTALL_NON_MARKET_APPS
-                            + " is deprecated. Please use the user restriction "
-                            + UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES + " instead.");
-                }
-                if (!mUserManager.isManagedProfile(callingUserId)) {
-                    Slog.e(LOG_TAG, "Ignoring setSecureSetting request for "
-                            + setting + ". User restriction "
-                            + UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES
-                            + " should be used instead.");
-                } else {
-                    try {
-                        setUserRestriction(who, UserManager.DISALLOW_INSTALL_UNKNOWN_SOURCES,
-                                (Integer.parseInt(value) == 0) ? true : false);
-                    } catch (NumberFormatException exc) {
-                        Slog.e(LOG_TAG, "Invalid value: " + value + " for setting " + setting);
-                    }
-                }
-                return;
-            }
+
             long id = mInjector.binderClearCallingIdentity();
             try {
                 if (Settings.Secure.DEFAULT_INPUT_METHOD.equals(setting)) {