diff --git a/libs/androidfw/ResourceTypes.cpp b/libs/androidfw/ResourceTypes.cpp
index 3fe75cffaa713..5b95c81db24eb 100644
--- a/libs/androidfw/ResourceTypes.cpp
+++ b/libs/androidfw/ResourceTypes.cpp
@@ -6880,6 +6880,9 @@ status_t ResTable::createIdmap(const ResTable& overlay,
         return UNKNOWN_ERROR;
     }
 
+    // The number of resources overlaid that were not explicitly marked overlayable.
+    size_t forcedOverlayCount = 0u;
+
     KeyedVector<uint8_t, IdmapTypeMap> map;
 
     // overlaid packages are assumed to contain only one package group
@@ -6919,6 +6922,7 @@ status_t ResTable::createIdmap(const ResTable& overlay,
                 continue;
             }
 
+            uint32_t typeSpecFlags = 0u;
             const String16 overlayType(resName.type, resName.typeLen);
             const String16 overlayName(resName.name, resName.nameLen);
             uint32_t overlayResID = overlay.identifierForName(overlayName.string(),
@@ -6926,14 +6930,23 @@ status_t ResTable::createIdmap(const ResTable& overlay,
                                                               overlayType.string(),
                                                               overlayType.size(),
                                                               overlayPackage.string(),
-                                                              overlayPackage.size());
+                                                              overlayPackage.size(),
+                                                              &typeSpecFlags);
             if (overlayResID == 0) {
+                // No such target resource was found.
                 if (typeMap.entryMap.isEmpty()) {
                     typeMap.entryOffset++;
                 }
                 continue;
             }
 
+            // Now that we know this is being overlaid, check if it can be, and emit a warning if
+            // it can't.
+            if ((dtohl(typeConfigs->typeSpecFlags[entryIndex]) &
+                    ResTable_typeSpec::SPEC_OVERLAYABLE) == 0) {
+                forcedOverlayCount++;
+            }
+
             if (typeMap.overlayTypeId == -1) {
                 typeMap.overlayTypeId = Res_GETTYPE(overlayResID) + 1;
             }
@@ -7012,6 +7025,10 @@ status_t ResTable::createIdmap(const ResTable& overlay,
         typeData += entryCount * 2;
     }
 
+    if (forcedOverlayCount > 0) {
+        ALOGW("idmap: overlaid %zu resources not marked overlayable", forcedOverlayCount);
+    }
+
     return NO_ERROR;
 }
 
diff --git a/libs/androidfw/tests/data/basic/basic.apk b/libs/androidfw/tests/data/basic/basic.apk
index 0c17328e86b22..18ef75e91dedc 100644
Binary files a/libs/androidfw/tests/data/basic/basic.apk and b/libs/androidfw/tests/data/basic/basic.apk differ
diff --git a/libs/androidfw/tests/data/basic/basic_de_fr.apk b/libs/androidfw/tests/data/basic/basic_de_fr.apk
index e45258c6a005e..767dff6fcfa5f 100644
Binary files a/libs/androidfw/tests/data/basic/basic_de_fr.apk and b/libs/androidfw/tests/data/basic/basic_de_fr.apk differ
diff --git a/libs/androidfw/tests/data/basic/basic_hdpi-v4.apk b/libs/androidfw/tests/data/basic/basic_hdpi-v4.apk
index 4ae1a7c87a704..58953f56d736d 100644
Binary files a/libs/androidfw/tests/data/basic/basic_hdpi-v4.apk and b/libs/androidfw/tests/data/basic/basic_hdpi-v4.apk differ
diff --git a/libs/androidfw/tests/data/basic/basic_xhdpi-v4.apk b/libs/androidfw/tests/data/basic/basic_xhdpi-v4.apk
index a240d4c06c1db..103f6565bb066 100644
Binary files a/libs/androidfw/tests/data/basic/basic_xhdpi-v4.apk and b/libs/androidfw/tests/data/basic/basic_xhdpi-v4.apk differ
diff --git a/libs/androidfw/tests/data/basic/basic_xxhdpi-v4.apk b/libs/androidfw/tests/data/basic/basic_xxhdpi-v4.apk
index fd3d9b233084e..61369d5067862 100644
Binary files a/libs/androidfw/tests/data/basic/basic_xxhdpi-v4.apk and b/libs/androidfw/tests/data/basic/basic_xxhdpi-v4.apk differ
diff --git a/libs/androidfw/tests/data/basic/build b/libs/androidfw/tests/data/basic/build
index d619800d6fc55..5682ed4d30413 100755
--- a/libs/androidfw/tests/data/basic/build
+++ b/libs/androidfw/tests/data/basic/build
@@ -19,11 +19,15 @@ set -e
 
 PATH_TO_FRAMEWORK_RES=${ANDROID_BUILD_TOP}/prebuilts/sdk/current/android.jar
 
-aapt package \
-    -M AndroidManifest.xml \
-    -S res \
-    -A assets \
+aapt2 compile --dir res -o compiled.flata
+aapt2 link \
     -I $PATH_TO_FRAMEWORK_RES \
-    --split hdpi --split xhdpi --split xxhdpi --split fr,de \
-    -F basic.apk \
-    -f
+    --manifest AndroidManifest.xml \
+    -A assets \
+    --split basic_hdpi-v4.apk:hdpi \
+    --split basic_xhdpi-v4.apk:xhdpi \
+    --split basic_xxhdpi-v4.apk:xxhdpi \
+    --split basic_de_fr.apk:de,fr \
+    -o basic.apk \
+    compiled.flata
+rm compiled.flata
diff --git a/libs/androidfw/tests/data/basic/res/values/values.xml b/libs/androidfw/tests/data/basic/res/values/values.xml
index 638c9832ab4cd..6c474596b5cd1 100644
--- a/libs/androidfw/tests/data/basic/res/values/values.xml
+++ b/libs/androidfw/tests/data/basic/res/values/values.xml
@@ -60,4 +60,9 @@
         <item>2</item>
         <item>3</item>
     </integer-array>
+
+    <overlayable>
+        <item type="string" name="test2" />
+        <item type="array" name="integerArray1" />
+    </overlayable>
 </resources>
diff --git a/libs/androidfw/tests/data/overlay/build b/libs/androidfw/tests/data/overlay/build
index 112f373ead30f..716b1bd9db647 100755
--- a/libs/androidfw/tests/data/overlay/build
+++ b/libs/androidfw/tests/data/overlay/build
@@ -17,4 +17,6 @@
 
 set -e
 
-aapt package -M AndroidManifest.xml -S res -F overlay.apk -f
+aapt2 compile --dir res -o compiled.flata
+aapt2 link --manifest AndroidManifest.xml -o overlay.apk compiled.flata
+rm compiled.flata
diff --git a/libs/androidfw/tests/data/overlay/overlay.apk b/libs/androidfw/tests/data/overlay/overlay.apk
index 40bf17c5951ae..33f961117c448 100644
Binary files a/libs/androidfw/tests/data/overlay/overlay.apk and b/libs/androidfw/tests/data/overlay/overlay.apk differ