diff --git a/services/backup/java/com/android/server/backup/BackupManagerService.java b/services/backup/java/com/android/server/backup/BackupManagerService.java
index f4dbb5a9b0b26..eabe21fed9df8 100644
--- a/services/backup/java/com/android/server/backup/BackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/BackupManagerService.java
@@ -401,45 +401,53 @@ public class BackupManagerService implements BackupManagerServiceInterface {
         @Override
         public void onUnlockUser(int userId) {
             if (userId == UserHandle.USER_SYSTEM) {
-                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup init");
-                sInstance.initialize(userId);
-                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
-
-                // Migrate legacy setting
-                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup migrate");
-                if (!backupSettingMigrated(userId)) {
-                    if (DEBUG) {
-                        Slog.i(TAG, "Backup enable apparently not migrated");
-                    }
-                    final ContentResolver r = sInstance.mContext.getContentResolver();
-                    final int enableState = Settings.Secure.getIntForUser(r,
-                            Settings.Secure.BACKUP_ENABLED, -1, userId);
-                    if (enableState >= 0) {
-                        if (DEBUG) {
-                            Slog.i(TAG, "Migrating enable state " + (enableState != 0));
-                        }
-                        writeBackupEnableState(enableState != 0, userId);
-                        Settings.Secure.putStringForUser(r,
-                                Settings.Secure.BACKUP_ENABLED, null, userId);
-                    } else {
-                        if (DEBUG) {
-                            Slog.i(TAG, "Backup not yet configured; retaining null enable state");
-                        }
-                    }
-                }
-                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
-
-                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup enable");
-                try {
-                    sInstance.setBackupEnabled(readBackupEnableState(userId));
-                } catch (RemoteException e) {
-                    // can't happen; it's a local object
-                }
-                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+                sInstance.unlockSystemUser();
             }
         }
     }
 
+    // Called through the trampoline from onUnlockUser(), then we buck the work
+    // off to the background thread to keep the unlock time down.
+    public void unlockSystemUser() {
+        mBackupHandler.post(() -> {
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup init");
+            sInstance.initialize(UserHandle.USER_SYSTEM);
+            Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+
+            // Migrate legacy setting
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup migrate");
+            if (!backupSettingMigrated(UserHandle.USER_SYSTEM)) {
+                if (DEBUG) {
+                    Slog.i(TAG, "Backup enable apparently not migrated");
+                }
+                final ContentResolver r = sInstance.mContext.getContentResolver();
+                final int enableState = Settings.Secure.getIntForUser(r,
+                        Settings.Secure.BACKUP_ENABLED, -1, UserHandle.USER_SYSTEM);
+                if (enableState >= 0) {
+                    if (DEBUG) {
+                        Slog.i(TAG, "Migrating enable state " + (enableState != 0));
+                    }
+                    writeBackupEnableState(enableState != 0, UserHandle.USER_SYSTEM);
+                    Settings.Secure.putStringForUser(r,
+                            Settings.Secure.BACKUP_ENABLED, null, UserHandle.USER_SYSTEM);
+                } else {
+                    if (DEBUG) {
+                        Slog.i(TAG, "Backup not yet configured; retaining null enable state");
+                    }
+                }
+            }
+            Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup enable");
+            try {
+                sInstance.setBackupEnabled(readBackupEnableState(UserHandle.USER_SYSTEM));
+            } catch (RemoteException e) {
+                // can't happen; it's a local object
+            }
+            Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+        });
+    }
+
     class ProvisionedObserver extends ContentObserver {
         public ProvisionedObserver(Handler handler) {
             super(handler);
diff --git a/services/backup/java/com/android/server/backup/BackupManagerServiceInterface.java b/services/backup/java/com/android/server/backup/BackupManagerServiceInterface.java
index 5dfa6302093e6..041f9ed5d0314 100644
--- a/services/backup/java/com/android/server/backup/BackupManagerServiceInterface.java
+++ b/services/backup/java/com/android/server/backup/BackupManagerServiceInterface.java
@@ -39,6 +39,8 @@ import java.io.PrintWriter;
  */
 public interface BackupManagerServiceInterface {
 
+  void unlockSystemUser();
+
   // Utility: build a new random integer token
   int generateRandomIntegerToken();
 
diff --git a/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java b/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java
index fe4902f8bf9da..f298065903a80 100644
--- a/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/RefactoredBackupManagerService.java
@@ -548,45 +548,53 @@ public class RefactoredBackupManagerService implements BackupManagerServiceInter
         @Override
         public void onUnlockUser(int userId) {
             if (userId == UserHandle.USER_SYSTEM) {
-                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup init");
-                sInstance.initialize(userId);
-                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
-
-                // Migrate legacy setting
-                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup migrate");
-                if (!backupSettingMigrated(userId)) {
-                    if (DEBUG) {
-                        Slog.i(TAG, "Backup enable apparently not migrated");
-                    }
-                    final ContentResolver r = sInstance.mContext.getContentResolver();
-                    final int enableState = Settings.Secure.getIntForUser(r,
-                            Settings.Secure.BACKUP_ENABLED, -1, userId);
-                    if (enableState >= 0) {
-                        if (DEBUG) {
-                            Slog.i(TAG, "Migrating enable state " + (enableState != 0));
-                        }
-                        writeBackupEnableState(enableState != 0, userId);
-                        Settings.Secure.putStringForUser(r,
-                                Settings.Secure.BACKUP_ENABLED, null, userId);
-                    } else {
-                        if (DEBUG) {
-                            Slog.i(TAG, "Backup not yet configured; retaining null enable state");
-                        }
-                    }
-                }
-                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
-
-                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup enable");
-                try {
-                    sInstance.setBackupEnabled(readBackupEnableState(userId));
-                } catch (RemoteException e) {
-                    // can't happen; it's a local object
-                }
-                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+                sInstance.unlockSystemUser();
             }
         }
     }
 
+    // Called through the trampoline from onUnlockUser(), then we buck the work
+    // off to the background thread to keep the unlock time down.
+    public void unlockSystemUser() {
+        mBackupHandler.post(() -> {
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup init");
+            sInstance.initialize(UserHandle.USER_SYSTEM);
+            Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+
+            // Migrate legacy setting
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup migrate");
+            if (!backupSettingMigrated(UserHandle.USER_SYSTEM)) {
+                if (DEBUG) {
+                    Slog.i(TAG, "Backup enable apparently not migrated");
+                }
+                final ContentResolver r = sInstance.mContext.getContentResolver();
+                final int enableState = Settings.Secure.getIntForUser(r,
+                        Settings.Secure.BACKUP_ENABLED, -1, UserHandle.USER_SYSTEM);
+                if (enableState >= 0) {
+                    if (DEBUG) {
+                        Slog.i(TAG, "Migrating enable state " + (enableState != 0));
+                    }
+                    writeBackupEnableState(enableState != 0, UserHandle.USER_SYSTEM);
+                    Settings.Secure.putStringForUser(r,
+                            Settings.Secure.BACKUP_ENABLED, null, UserHandle.USER_SYSTEM);
+                } else {
+                    if (DEBUG) {
+                        Slog.i(TAG, "Backup not yet configured; retaining null enable state");
+                    }
+                }
+            }
+            Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup enable");
+            try {
+                sInstance.setBackupEnabled(readBackupEnableState(UserHandle.USER_SYSTEM));
+            } catch (RemoteException e) {
+                // can't happen; it's a local object
+            }
+            Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+        });
+    }
+
     // Bookkeeping of in-flight operations for timeout etc. purposes.  The operation
     // token is the index of the entry in the pending-operations list.
     public static final int OP_PENDING = 0;
diff --git a/services/backup/java/com/android/server/backup/Trampoline.java b/services/backup/java/com/android/server/backup/Trampoline.java
index 245bc1dfd3bf2..9739e38055b8b 100644
--- a/services/backup/java/com/android/server/backup/Trampoline.java
+++ b/services/backup/java/com/android/server/backup/Trampoline.java
@@ -139,6 +139,13 @@ public class Trampoline extends IBackupManager.Stub {
         }
     }
 
+    void unlockSystemUser() {
+        BackupManagerServiceInterface svc = mService;
+        if (svc != null) {
+            svc.unlockSystemUser();
+        }
+    }
+
     public void setBackupServiceActive(final int userHandle, boolean makeActive) {
         // Only the DPM should be changing the active state of backup
         final int caller = binderGetCallingUid();