diff --git a/validator/.idea/runConfigurations/WritebackValidator_writeback_states.xml b/validator/.idea/runConfigurations/WritebackSequences_writeback_states.xml
similarity index 74%
rename from validator/.idea/runConfigurations/WritebackValidator_writeback_states.xml
rename to validator/.idea/runConfigurations/WritebackSequences_writeback_states.xml
index da9a2c99fc..5d663011cf 100644
--- a/validator/.idea/runConfigurations/WritebackValidator_writeback_states.xml
+++ b/validator/.idea/runConfigurations/WritebackSequences_writeback_states.xml
@@ -1,5 +1,5 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="WritebackValidator.writeback_states" type="JUnit" factoryName="JUnit" nameIsGenerated="true">
+  <configuration default="false" name="WritebackSequences.writeback_states" type="JUnit" factoryName="JUnit" nameIsGenerated="true">
     <module name="validator" />
     <extension name="coverage">
       <pattern>
@@ -7,8 +7,8 @@
         <option name="ENABLED" value="true" />
       </pattern>
     </extension>
-    <option name="PACKAGE_NAME" value="com.google.daq.mqtt.validator.validations" />
-    <option name="MAIN_CLASS_NAME" value="com.google.daq.mqtt.validator.validations.WritebackValidator" />
+    <option name="PACKAGE_NAME" value="com.google.daq.mqtt.sequencer.sequences" />
+    <option name="MAIN_CLASS_NAME" value="com.google.daq.mqtt.sequencer.sequences.WritebackSequences" />
     <option name="METHOD_NAME" value="writeback_states" />
     <option name="TEST_OBJECT" value="method" />
     <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/.." />
diff --git a/validator/src/main/java/com/google/daq/mqtt/util/ConfigDiffEngine.java b/validator/src/main/java/com/google/daq/mqtt/util/ConfigDiffEngine.java
index 288ecaaec3..30daa0f704 100644
--- a/validator/src/main/java/com/google/daq/mqtt/util/ConfigDiffEngine.java
+++ b/validator/src/main/java/com/google/daq/mqtt/util/ConfigDiffEngine.java
@@ -1,7 +1,5 @@
 package com.google.daq.mqtt.util;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableMap;
 import com.google.daq.mqtt.sequencer.semantic.SemanticValue;
@@ -25,8 +23,7 @@ public ConfigDiffEngine() {
   }
 
   /**
-   * Compute the changes in a config object from the previous config, as
-   * stored in the class.
+   * Compute the changes in a config object from the previous config, as stored in the class.
    *
    * @param deviceConfig new config
    * @return list of differences against the previous config
@@ -40,16 +37,24 @@ public List<String> computeChanges(Config deviceConfig) {
     return configUpdates;
   }
 
+  @SuppressWarnings("unchecked")
   private Map<String, Object> convertSemantics(Object thing) {
-    return thing == null ? ImmutableMap.of() :
-        Arrays.stream(thing.getClass().getFields())
-            .filter(field -> isNotNull(thing, field)).collect(
-                Collectors.toMap(Field::getName, field -> convertSemantics(thing, field)));
+    if (thing == null) {
+      return ImmutableMap.of();
+    }
+    if (thing instanceof Map) {
+      Map<String, Object> asMap = (Map<String, Object>) thing;
+      return asMap.keySet().stream()
+          .collect(Collectors.toMap(key -> key, key -> convertSemantics(asMap.get(key))));
+    }
+    return Arrays.stream(thing.getClass().getFields())
+        .filter(field -> isNotNull(thing, field)).collect(
+            Collectors.toMap(Field::getName, field -> convertSemantics(thing, field)));
   }
 
   private Object convertSemantics(Object thing, Field field) {
     try {
-      if (isBaseType(field)) {
+      if (isBaseType(field) || isBaseType(field.get(thing))) {
         return field.get(thing);
       } else {
         return convertSemantics(field.get(thing));
@@ -69,7 +74,9 @@ private boolean isNotNull(Object thing, Field field) {
 
   private boolean isBaseType(Object value) {
     Class<?> type = value instanceof Field ? ((Field) value).getType() : value.getClass();
-    return Integer.class.isAssignableFrom(type)
+    return type.isPrimitive()
+        || Boolean.class.isAssignableFrom(type)
+        || Integer.class.isAssignableFrom(type)
         || String.class.isAssignableFrom(type)
         || Date.class.isAssignableFrom(type);
   }