diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/HighFunctionDBUtil.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/HighFunctionDBUtil.java
index ff7473569b..d7ea18c3ee 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/HighFunctionDBUtil.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/HighFunctionDBUtil.java
@@ -19,6 +19,7 @@ import java.util.*;
 
 import ghidra.program.model.address.*;
 import ghidra.program.model.data.*;
+import ghidra.program.model.lang.PrototypeModel;
 import ghidra.program.model.lang.Register;
 import ghidra.program.model.listing.*;
 import ghidra.program.model.listing.Function.FunctionUpdateType;
@@ -39,6 +40,38 @@ public class HighFunctionDBUtil {
 
 	public static final String AUTO_CAT = "/auto_proto"; // Category for auto generated prototypes
 
+	/**
+	 * Return the appropriate model name for committing to the database with the given HighFunction.
+	 * Generally this just returns the model name attached to the HighFunction, but if the "unknown"
+	 * model is associated with the function, or if the model doesn't exist, the decompiler
+	 * was using the "default" model internally, so this is the more appropriate model to commit.
+	 * Its possible for this routine to return null, if the architecture has no default model.
+	 * @param highFunction is the given HighFunction
+	 * @return the model name to commit
+	 */
+	private static String getPrototypeModelForCommit(HighFunction highFunction) {
+		FunctionPrototype prototype = highFunction.getFunctionPrototype();
+		String modelName = (prototype != null) ? prototype.getModelName() : null;
+		if (modelName != null) {
+			if (modelName.equals(Function.UNKNOWN_CALLING_CONVENTION_STRING)) {
+				modelName = null;
+			}
+			else {
+				if (null == highFunction.getCompilerSpec().getCallingConvention(modelName)) {
+					modelName = null;
+				}
+			}
+		}
+		if (modelName == null) {
+			// Currently the decompiler uses the default convention to model an unknown convention
+			PrototypeModel model = highFunction.getCompilerSpec().getDefaultCallingConvention();
+			if (model != null) {
+				modelName = model.getName();
+			}
+		}
+		return modelName;
+	}
+
 	/**
 	 * Commit the decompiler's version of the function return data-type to the database.
 	 * The decompiler's version of the prototype model is committed as well
@@ -51,7 +84,7 @@ public class HighFunctionDBUtil {
 			// Change calling convention if needed
 			Function function = highFunction.getFunction();
 			String convention = function.getCallingConventionName();
-			String modelName = highFunction.getFunctionPrototype().getModelName();
+			String modelName = getPrototypeModelForCommit(highFunction);
 			if (modelName != null && !modelName.equals(convention)) {
 				function.setCallingConvention(modelName);
 			}
@@ -84,8 +117,7 @@ public class HighFunctionDBUtil {
 
 		List<Parameter> params = getParameters(highFunction, useDataTypes);
 
-		FunctionPrototype functionPrototype = highFunction.getFunctionPrototype();
-		String modelName = (functionPrototype != null) ? functionPrototype.getModelName() : null;
+		String modelName = getPrototypeModelForCommit(highFunction);
 		commitParamsToDatabase(function, modelName, params,
 			highFunction.getFunctionPrototype().isVarArg(), true, source);
 	}