diff --git a/libs/surfaceflinger/LayerBase.cpp b/libs/surfaceflinger/LayerBase.cpp
index 9ddf972..ec38fe9 100644
--- a/libs/surfaceflinger/LayerBase.cpp
+++ b/libs/surfaceflinger/LayerBase.cpp
@@ -398,7 +398,8 @@
     glEnable(GL_TEXTURE_2D);
 
     // Dithering...
-    if (s.flags & ISurfaceComposer::eLayerDither) {
+    bool fast = !(mFlags & DisplayHardware::SLOW_CONFIG);
+    if (fast || s.flags & ISurfaceComposer::eLayerDither) {
         glEnable(GL_DITHER);
     } else {
         glDisable(GL_DITHER);
diff --git a/libs/surfaceflinger/SurfaceFlinger.cpp b/libs/surfaceflinger/SurfaceFlinger.cpp
index a72294a..c78921a 100644
--- a/libs/surfaceflinger/SurfaceFlinger.cpp
+++ b/libs/surfaceflinger/SurfaceFlinger.cpp
@@ -573,8 +573,10 @@
     // do this without lock held
     const size_t count = ditchedLayers.size();
     for (size_t i=0 ; i<count ; i++) {
-        //LOGD("ditching layer %p", ditchedLayers[i].get());
-        ditchedLayers[i]->ditch();
+        if (ditchedLayers[i] != 0) {
+            //LOGD("ditching layer %p", ditchedLayers[i].get());
+            ditchedLayers[i]->ditch();
+        }
     }
 }
 
@@ -1082,6 +1084,8 @@
 
 status_t SurfaceFlinger::addLayer_l(const sp<LayerBase>& layer)
 {
+    if (layer == 0)
+        return BAD_VALUE;
     ssize_t i = mCurrentState.layersSortedByZ.add(
                 layer, &LayerBase::compareCurrentStateZ);
     sp<LayerBaseClient> lbc = LayerBase::dynamicCast< LayerBaseClient* >(layer.get());