diff --git a/src/com/android/launcher3/model/GridSizeMigrationUtil.java b/src/com/android/launcher3/model/GridSizeMigrationUtil.java
index d63408b..eded5ea 100644
--- a/src/com/android/launcher3/model/GridSizeMigrationUtil.java
+++ b/src/com/android/launcher3/model/GridSizeMigrationUtil.java
@@ -66,7 +66,7 @@
 public class GridSizeMigrationUtil {
 
     private static final String TAG = "GridSizeMigrationUtil";
-    private static final boolean DEBUG = false;
+    private static final boolean DEBUG = true;
 
     private GridSizeMigrationUtil() {
         // Util class should not be instantiated
@@ -188,27 +188,54 @@
             @NonNull final DeviceGridState srcDeviceState,
             @NonNull final DeviceGridState destDeviceState) {
 
-        final List<DbEntry> hotseatItems = destReader.loadHotseatEntries();
-        final List<DbEntry> workspaceItems = destReader.loadAllWorkspaceEntries();
-        final List<DbEntry> hotseatDiff =
-                calcDiff(srcReader.loadHotseatEntries(), hotseatItems);
-        final List<DbEntry> workspaceDiff =
-                calcDiff(srcReader.loadAllWorkspaceEntries(), workspaceItems);
+        final List<DbEntry> srcHotseatItems = srcReader.loadHotseatEntries();
+        final List<DbEntry> srcWorkspaceItems = srcReader.loadAllWorkspaceEntries();
+        final List<DbEntry> dstHotseatItems = destReader.loadHotseatEntries();
+        final List<DbEntry> dstWorkspaceItems = destReader.loadAllWorkspaceEntries();
+        final List<DbEntry> hotseatToBeAdded = new ArrayList<>(1);
+        final List<DbEntry> workspaceToBeAdded = new ArrayList<>(1);
+        final IntArray toBeRemoved = new IntArray();
+
+        calcDiff(srcHotseatItems, dstHotseatItems, hotseatToBeAdded, toBeRemoved);
+        calcDiff(srcWorkspaceItems, dstWorkspaceItems, workspaceToBeAdded, toBeRemoved);
 
         final int trgX = targetSize.x;
         final int trgY = targetSize.y;
 
-        if (hotseatDiff.isEmpty() && workspaceDiff.isEmpty()) {
+        if (DEBUG) {
+            Log.d(TAG, "Start migration:"
+                    + "\n Source Device:"
+                    + srcWorkspaceItems.stream().map(DbEntry::toString).collect(
+                    Collectors.joining(",\n", "[", "]"))
+                    + "\n Target Device:"
+                    + dstWorkspaceItems.stream().map(DbEntry::toString).collect(
+                    Collectors.joining(",\n", "[", "]"))
+                    + "\n Removing Items:"
+                    + dstWorkspaceItems.stream().filter(entry ->
+                            toBeRemoved.contains(entry.id)).map(DbEntry::toString).collect(
+                    Collectors.joining(",\n", "[", "]"))
+                    + "\n Adding Workspace Items:"
+                    + workspaceToBeAdded.stream().map(DbEntry::toString).collect(
+                    Collectors.joining(",\n", "[", "]"))
+                    + "\n Adding Hotseat Items:"
+                    + hotseatToBeAdded.stream().map(DbEntry::toString).collect(
+                    Collectors.joining(",\n", "[", "]"))
+            );
+        }
+        if (!toBeRemoved.isEmpty()) {
+            removeEntryFromDb(destReader.mDb, destReader.mTableName, toBeRemoved);
+        }
+        if (hotseatToBeAdded.isEmpty() && workspaceToBeAdded.isEmpty()) {
             return false;
         }
 
         // Sort the items by the reading order.
-        Collections.sort(hotseatDiff);
-        Collections.sort(workspaceDiff);
+        Collections.sort(hotseatToBeAdded);
+        Collections.sort(workspaceToBeAdded);
 
         // Migrate hotseat
         solveHotseatPlacement(db, srcReader,
-                destReader, context, destHotseatSize, hotseatItems, hotseatDiff);
+                destReader, context, destHotseatSize, dstHotseatItems, hotseatToBeAdded);
 
         // Migrate workspace.
         // First we create a collection of the screens
@@ -229,8 +256,8 @@
                 Log.d(TAG, "Migrating " + screenId);
             }
             solveGridPlacement(db, srcReader,
-                    destReader, context, screenId, trgX, trgY, workspaceDiff, false);
-            if (workspaceDiff.isEmpty()) {
+                    destReader, context, screenId, trgX, trgY, workspaceToBeAdded, false);
+            if (workspaceToBeAdded.isEmpty()) {
                 break;
             }
         }
@@ -238,42 +265,37 @@
         // In case the new grid is smaller, there might be some leftover items that don't fit on
         // any of the screens, in this case we add them to new screens until all of them are placed.
         int screenId = destReader.mLastScreenId + 1;
-        while (!workspaceDiff.isEmpty()) {
+        while (!workspaceToBeAdded.isEmpty()) {
             solveGridPlacement(db, srcReader,
-                    destReader, context, screenId, trgX, trgY, workspaceDiff, preservePages);
+                    destReader, context, screenId, trgX, trgY, workspaceToBeAdded, preservePages);
             screenId++;
         }
 
         return true;
     }
 
-    /** Return what's in the src but not in the dest */
-    private static List<DbEntry> calcDiff(List<DbEntry> src, List<DbEntry> dest) {
-        Map<String, Integer> destIdSet = new HashMap<>();
-        for (DbEntry entry : dest) {
-            String entryID = entry.getEntryMigrationId();
-            if (destIdSet.containsKey(entryID)) {
-                destIdSet.put(entryID, destIdSet.get(entryID) + 1);
-            } else {
-                destIdSet.put(entryID, 1);
+    /**
+     * Calculate the differences between {@code src} (denoted by A) and {@code dest}
+     * (denoted by B).
+     * All DbEntry in A - B will be added to {@code toBeAdded}
+     * All DbEntry.id in B - A will be added to {@code toBeRemoved}
+     */
+    private static void calcDiff(@NonNull final List<DbEntry> src,
+            @NonNull final List<DbEntry> dest, @NonNull final List<DbEntry> toBeAdded,
+            @NonNull final IntArray toBeRemoved) {
+        src.forEach(entry -> {
+            if (!dest.contains(entry)) {
+                toBeAdded.add(entry);
             }
-        }
-        List<DbEntry> diff = new ArrayList<>();
-        for (DbEntry entry : src) {
-            String entryID = entry.getEntryMigrationId();
-            if (destIdSet.containsKey(entryID)) {
-                Integer count = destIdSet.get(entryID);
-                if (count <= 0) {
-                    diff.add(entry);
-                    destIdSet.remove(entryID);
-                } else {
-                    destIdSet.put(entryID, count - 1);
+        });
+        dest.forEach(entry -> {
+            if (!src.contains(entry)) {
+                toBeRemoved.add(entry.id);
+                if (entry.itemType == LauncherSettings.Favorites.ITEM_TYPE_FOLDER) {
+                    entry.mFolderItems.values().forEach(ids -> ids.forEach(toBeRemoved::add));
                 }
-            } else {
-                diff.add(entry);
             }
-        }
-        return diff;
+        });
     }
 
     private static void insertEntryInDb(SQLiteDatabase db, Context context, DbEntry entry,
@@ -682,12 +704,12 @@
             if (this == o) return true;
             if (o == null || getClass() != o.getClass()) return false;
             DbEntry entry = (DbEntry) o;
-            return Objects.equals(mIntent, entry.mIntent);
+            return Objects.equals(getEntryMigrationId(), entry.getEntryMigrationId());
         }
 
         @Override
         public int hashCode() {
-            return Objects.hash(mIntent);
+            return Objects.hash(getEntryMigrationId());
         }
 
         public void updateContentValues(ContentValues values) {
diff --git a/tests/src/com/android/launcher3/model/GridSizeMigrationUtilTest.kt b/tests/src/com/android/launcher3/model/GridSizeMigrationUtilTest.kt
index 85d7bf9..76a186b 100644
--- a/tests/src/com/android/launcher3/model/GridSizeMigrationUtilTest.kt
+++ b/tests/src/com/android/launcher3/model/GridSizeMigrationUtilTest.kt
@@ -17,6 +17,7 @@
 
 import android.content.Context
 import android.content.Intent
+import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase
 import android.graphics.Point
 import android.os.Process
@@ -183,15 +184,232 @@
         // Expected dest grid icons
         // _ _ _ _
         // 5 6 7 8
-        // 9 _ 10_
+        // 9 _ _ _
         // _ _ _ _
-        assertThat(locMap.size.toLong()).isEqualTo(6)
+        assertThat(locMap.size.toLong()).isEqualTo(5)
         assertThat(locMap[testPackage5]).isEqualTo(Point(0, 1))
         assertThat(locMap[testPackage6]).isEqualTo(Point(1, 1))
         assertThat(locMap[testPackage7]).isEqualTo(Point(2, 1))
         assertThat(locMap[testPackage8]).isEqualTo(Point(3, 1))
         assertThat(locMap[testPackage9]).isEqualTo(Point(0, 2))
-        assertThat(locMap[testPackage10]).isEqualTo(Point(2, 2))
+    }
+
+    /**
+     * Old migration logic, should be modified once [FeatureFlags.ENABLE_NEW_MIGRATION_LOGIC] is
+     * not needed anymore
+     */
+    @Test
+    @Throws(Exception::class)
+    fun testMigrationBackAndForth() {
+        // Hotseat items in grid A
+        // 1 2 _ 3 4
+        modelHelper.addItem(APP_ICON, 0, HOTSEAT, 0, 0, testPackage1, 1, TMP_CONTENT_URI)
+        modelHelper.addItem(SHORTCUT, 1, HOTSEAT, 0, 0, testPackage2, 2, TMP_CONTENT_URI)
+        modelHelper.addItem(SHORTCUT, 3, HOTSEAT, 0, 0, testPackage3, 3, TMP_CONTENT_URI)
+        modelHelper.addItem(APP_ICON, 4, HOTSEAT, 0, 0, testPackage4, 4, TMP_CONTENT_URI)
+        // Workspace items in grid A
+        // _ _ _ _ _
+        // _ _ _ _ 5
+        // _ _ 6 _ 7
+        // _ _ 8 _ _
+        // _ _ _ _ _
+        modelHelper.addItem(APP_ICON, 0, DESKTOP, 4, 1, testPackage5, 5, TMP_CONTENT_URI)
+        modelHelper.addItem(APP_ICON, 0, DESKTOP, 2, 2, testPackage6, 6, TMP_CONTENT_URI)
+        modelHelper.addItem(APP_ICON, 0, DESKTOP, 4, 2, testPackage7, 7, TMP_CONTENT_URI)
+        modelHelper.addItem(APP_ICON, 0, DESKTOP, 2, 3, testPackage8, 8, TMP_CONTENT_URI)
+
+        // Hotseat items in grid B
+        // 2 _ _ _
+        modelHelper.addItem(SHORTCUT, 0, HOTSEAT, 0, 0, testPackage2)
+        // Workspace items in grid B
+        // _ _ _ _
+        // _ _ _ 10
+        // _ _ _ _
+        // _ _ _ _
+        modelHelper.addItem(APP_ICON, 0, DESKTOP, 1, 3, testPackage10)
+
+        idp.numDatabaseHotseatIcons = 4
+        idp.numColumns = 4
+        idp.numRows = 4
+        val readerGridA = DbReader(db, TMP_TABLE, context, validPackages)
+        val readerGridB = DbReader(db, TABLE_NAME, context, validPackages)
+        // migrate from A -> B
+        GridSizeMigrationUtil.migrate(
+                context,
+                db,
+                readerGridA,
+                readerGridB,
+                idp.numDatabaseHotseatIcons,
+                Point(idp.numColumns, idp.numRows),
+                DeviceGridState(context),
+                DeviceGridState(idp)
+        )
+
+        // Check hotseat items in grid B
+        var c = context.contentResolver.query(
+                CONTENT_URI,
+                arrayOf(SCREEN, INTENT),
+                "container=$CONTAINER_HOTSEAT",
+                null,
+                SCREEN,
+                null
+        ) ?: throw IllegalStateException()
+        // Expected hotseat items in grid B
+        // 2 1 3 4
+        verifyHotseat(c, idp,
+                mutableListOf(testPackage2, testPackage1, testPackage3, testPackage4).toList())
+
+        // Check workspace items in grid B
+        c = context.contentResolver.query(
+                CONTENT_URI,
+                arrayOf(SCREEN, CELLX, CELLY, INTENT),
+                "container=$CONTAINER_DESKTOP",
+                null,
+                null,
+                null
+        ) ?: throw IllegalStateException()
+        var locMap = parseLocMap(context, c)
+        // Expected items in grid B
+        // _ _ _ _
+        // 5 6 7 8
+        // _ _ _ _
+        // _ _ _ _
+        assertThat(locMap.size.toLong()).isEqualTo(4)
+        assertThat(locMap[testPackage5]).isEqualTo(Triple(0, 0, 1))
+        assertThat(locMap[testPackage6]).isEqualTo(Triple(0, 1, 1))
+        assertThat(locMap[testPackage7]).isEqualTo(Triple(0, 2, 1))
+        assertThat(locMap[testPackage8]).isEqualTo(Triple(0, 3, 1))
+
+        // add item in B
+        modelHelper.addItem(APP_ICON, 0, DESKTOP, 0, 2, testPackage9)
+
+        // migrate from B -> A
+        GridSizeMigrationUtil.migrate(
+                context,
+                db,
+                readerGridB,
+                readerGridA,
+                5,
+                Point(5, 5),
+                DeviceGridState(idp),
+                DeviceGridState(context)
+        )
+        // Check hotseat items in grid A
+        c = context.contentResolver.query(
+                TMP_CONTENT_URI,
+                arrayOf(SCREEN, INTENT),
+                "container=$CONTAINER_HOTSEAT",
+                null,
+                SCREEN,
+                null
+        ) ?: throw IllegalStateException()
+        // Expected hotseat items in grid A
+        // 1 2 _ 3 4
+        verifyHotseat(c, idp, mutableListOf(
+                testPackage1, testPackage2, null, testPackage3, testPackage4).toList())
+
+        // Check workspace items in grid A
+        c = context.contentResolver.query(
+                TMP_CONTENT_URI,
+                arrayOf(SCREEN, CELLX, CELLY, INTENT),
+                "container=$CONTAINER_DESKTOP",
+                null,
+                null,
+                null
+        ) ?: throw IllegalStateException()
+        locMap = parseLocMap(context, c)
+        // Expected workspace items in grid A
+        // _ _ _ _ _
+        // _ _ _ _ 5
+        // 9 _ 6 _ 7
+        // _ _ 8 _ _
+        // _ _ _ _ _
+        assertThat(locMap.size.toLong()).isEqualTo(5)
+        // Verify items that existed in grid A remains in same position
+        assertThat(locMap[testPackage5]).isEqualTo(Triple(0, 4, 1))
+        assertThat(locMap[testPackage6]).isEqualTo(Triple(0, 2, 2))
+        assertThat(locMap[testPackage7]).isEqualTo(Triple(0, 4, 2))
+        assertThat(locMap[testPackage8]).isEqualTo(Triple(0, 2, 3))
+        // Verify items that didn't exist in grid A are added in new screen
+        assertThat(locMap[testPackage9]).isEqualTo(Triple(0, 0, 2))
+
+        // remove item from B
+        modelHelper.deleteItem(7, TMP_TABLE)
+
+        // migrate from A -> B
+        GridSizeMigrationUtil.migrate(
+                context,
+                db,
+                readerGridA,
+                readerGridB,
+                idp.numDatabaseHotseatIcons,
+                Point(idp.numColumns, idp.numRows),
+                DeviceGridState(context),
+                DeviceGridState(idp)
+        )
+
+        // Check hotseat items in grid B
+        c = context.contentResolver.query(
+                CONTENT_URI,
+                arrayOf(SCREEN, INTENT),
+                "container=$CONTAINER_HOTSEAT",
+                null,
+                SCREEN,
+                null
+        ) ?: throw IllegalStateException()
+        // Expected hotseat items in grid B
+        // 2 1 3 4
+        verifyHotseat(c, idp,
+                mutableListOf(testPackage2, testPackage1, testPackage3, testPackage4).toList())
+
+        // Check workspace items in grid B
+        c = context.contentResolver.query(
+                CONTENT_URI,
+                arrayOf(SCREEN, CELLX, CELLY, INTENT),
+                "container=$CONTAINER_DESKTOP",
+                null,
+                null,
+                null
+        ) ?: throw IllegalStateException()
+        locMap = parseLocMap(context, c)
+        // Expected workspace items in grid B
+        // _ _ _ _
+        // 5 6 _ 8
+        // 9 _ _ _
+        // _ _ _ _
+        assertThat(locMap.size.toLong()).isEqualTo(4)
+        assertThat(locMap[testPackage5]).isEqualTo(Triple(0, 0, 1))
+        assertThat(locMap[testPackage6]).isEqualTo(Triple(0, 1, 1))
+        assertThat(locMap[testPackage8]).isEqualTo(Triple(0, 3, 1))
+        assertThat(locMap[testPackage9]).isEqualTo(Triple(0, 0, 2))
+    }
+
+    private fun verifyHotseat(c: Cursor, idp: InvariantDeviceProfile, expected: List<String?>) {
+        assertThat(c.count).isEqualTo(idp.numDatabaseHotseatIcons)
+        val screenIndex = c.getColumnIndex(SCREEN)
+        val intentIndex = c.getColumnIndex(INTENT)
+        expected.forEachIndexed { idx, pkg ->
+            if (pkg == null) return@forEachIndexed
+            c.moveToNext()
+            assertThat(c.getInt(screenIndex).toLong()).isEqualTo(idx)
+            assertThat(c.getString(intentIndex)).contains(pkg)
+        }
+        c.close()
+    }
+
+    private fun parseLocMap(context: Context, c: Cursor): Map<String, Triple<Int, Int, Int>> {
+        // Check workspace items
+        val intentIndex = c.getColumnIndex(INTENT)
+        val screenIndex = c.getColumnIndex(SCREEN)
+        val cellXIndex = c.getColumnIndex(CELLX)
+        val cellYIndex = c.getColumnIndex(CELLY)
+        val locMap = mutableMapOf<String, Triple<Int, Int, Int>>()
+        while (c.moveToNext()) {
+            locMap[Intent.parseUri(c.getString(intentIndex), 0).getPackage()] =
+                    Triple(c.getInt(screenIndex), c.getInt(cellXIndex), c.getInt(cellYIndex))
+        }
+        c.close()
+        return locMap.toMap()
     }
 
     @Test
diff --git a/tests/src/com/android/launcher3/util/LauncherModelHelper.java b/tests/src/com/android/launcher3/util/LauncherModelHelper.java
index e7e551f..93bf312 100644
--- a/tests/src/com/android/launcher3/util/LauncherModelHelper.java
+++ b/tests/src/com/android/launcher3/util/LauncherModelHelper.java
@@ -362,6 +362,12 @@
         sandboxContext.getContentResolver().insert(contentUri, values);
     }
 
+    public void deleteItem(int itemId, @NonNull final String tableName) {
+        final Uri uri = Uri.parse("content://"
+                + LauncherProvider.AUTHORITY + "/" + tableName + "/" + itemId);
+        sandboxContext.getContentResolver().delete(uri, null, null);
+    }
+
     public int[][][] createGrid(int[][][] typeArray) {
         return createGrid(typeArray, 1);
     }