diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/function/FunctionDB.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/function/FunctionDB.java
index ace0699cd5..50a6ff780c 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/function/FunctionDB.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/function/FunctionDB.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -2470,16 +2470,6 @@ public class FunctionDB extends DatabaseObject implements Function {
 				return thunkedFunction.getSignatureSource();
 			}
 
-			// Force DEFAULT source if any param has unassigned storage
-			if (!getReturn().isValid()) {
-				return SourceType.DEFAULT;
-			}
-			for (Parameter param : getParameters()) {
-				if (!param.isValid()) {
-					return SourceType.DEFAULT;
-				}
-			}
-
 			return getStoredSignatureSource();
 		}
 		finally {
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/LocalSymbolMap.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/LocalSymbolMap.java
index c4179411f2..9209d212d1 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/LocalSymbolMap.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/LocalSymbolMap.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -210,11 +210,12 @@ public class LocalSymbolMap {
 		pcaddr = pcaddr.subtractWrap(1);
 
 		List<HighSymbol> paramList = new ArrayList<>();
+		boolean internalInvalid = false;
 		for (int i = 0; i < p.length; ++i) {
 			Parameter var = p[i];
 			if (!var.isValid()) {
-				// TODO: exclude parameters which don't have valid storage ??
-				continue;
+				internalInvalid = true;
+				break;
 			}
 			DataType dt = var.getDataType();
 			String name = var.getName();
@@ -243,6 +244,12 @@ public class LocalSymbolMap {
 			paramSymbol.setNameLock(namelock);
 			paramSymbol.setTypeLock(lock);
 		}
+		if (internalInvalid) {
+			// Can only send down a partial prototype.  Let decompiler try to recover the whole.
+			for (HighSymbol paramSymbol : paramList) {
+				paramSymbol.setTypeLock(false);
+			}
+		}
 
 		paramSymbols = new HighSymbol[paramList.size()];
 		paramList.toArray(paramSymbols);
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/PcodeDataTypeManager.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/PcodeDataTypeManager.java
index 9af94f1f9c..5e5d057aee 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/PcodeDataTypeManager.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/PcodeDataTypeManager.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -1145,10 +1145,7 @@ public class PcodeDataTypeManager {
 	private void generateCoreTypes() {
 		voidDt = new VoidDataType(progDataTypes);
 		coreBuiltin = new HashMap<Long, TypeMap>();
-		TypeMap type = new TypeMap(DataType.DEFAULT, "undefined", "unknown", false, false,
-			DEFAULT_DECOMPILER_ID);
-		coreBuiltin.put(type.id, type);
-		type = new TypeMap(displayLanguage, VoidDataType.dataType, "void", false, false,
+		TypeMap type = new TypeMap(displayLanguage, VoidDataType.dataType, "void", false, false,
 			builtInDataTypes);
 		coreBuiltin.put(type.id, type);