diff --git a/indra/llrender/llvertexbuffer.cpp b/indra/llrender/llvertexbuffer.cpp
index 8d927ada5..1c227eb30 100644
--- a/indra/llrender/llvertexbuffer.cpp
+++ b/indra/llrender/llvertexbuffer.cpp
@@ -1299,7 +1299,31 @@ void LLVertexBuffer::setupVertexBuffer(U32 data_mask) const
 
 	if ((data_mask & mTypeMask) != data_mask)
 	{
-		llerrs << "LLVertexBuffer::setupVertexBuffer missing required components for supplied data mask." << llendl;
+		llerrs << "LLVertexBuffer::setupVertexBuffer missing required components for supplied data mask. Missing: ";
+
+		static const char* mask_names[] = {"VERTEX","NORMAL","TEXCOORD0","TEXCOORD1","TEXCOORD2","TEXCOORD3","COLOR","BINORMAL","WEIGHT","CLOTH_WEIGHT"};
+		for(int i = 0; i < 32; ++i)
+		{
+			if((data_mask & (1<<i)) && !(mTypeMask & (1<<i)))
+			{
+				if(i < (sizeof(mask_names)/sizeof(mask_names[0])))
+					llcont << "MAP_" << mask_names[i] << ", ";
+				else
+					llcont << "MAP_UNKNOWN (1<<" << i << "), ";
+			}
+		}
+		llcont << "\n Has: ";
+		for(int i = 0; i < 32; ++i)
+		{
+			if(mTypeMask & (1<<i))
+			{
+				if(i < (sizeof(mask_names)/sizeof(mask_names[0])))
+					llcont << "MASK_" << mask_names[i] << ", ";
+				else
+					llcont << "MAP_UNKNOWN (1<<" << i << "), ";
+			}
+		}
+		llcont << llendl;
 	}
 
 	if (data_mask & MAP_NORMAL)
diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index ff4be51aa..62c9ec640 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -2708,9 +2708,11 @@ void LLVolumeGeometryManager::genDrawInfo(LLSpatialGroup* group, U32 mask, std::
 		{
 			if (LLVertexBuffer::sEnableVBOs && buffer->getUsage() != group->mBufferUsage)
 			{
-				buffer = createVertexBuffer(group->mSpatialPartition->mVertexDataMask, 
+				//Using group->mSpatialPartition->mVertexDataMask may be dropping MAP_BINORMAL on RENDER_BUMP...
+				buffer = createVertexBuffer(mask /*group->mSpatialPartition->mVertexDataMask*/, 
 											group->mBufferUsage);
 				buffer->allocateBuffer(geom_count, index_count, TRUE);
+				llassert_always(buffer->getTypeMask() == mask);
 			}
 			else
 			{