diff --git a/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryCommandStreamStore.java b/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryCommandStreamStore.java
index 7b9f5a5cc..6755aacea 100644
--- a/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryCommandStreamStore.java
+++ b/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryCommandStreamStore.java
@@ -273,8 +273,13 @@ protected synchronized ICommandStreamInfo put(CommandStreamKey csKey, ICommandSt
                 var newValidTime = csInfo.getValidTime().begin();
                 
                 // error if command stream with same system/name/validTime already exists
+                // unless updating the same key
                 if (prevValidTime.equals(newValidTime))
+                {
+                    if (replace && key.equals(csKey))
+                        return map.put(csKey, csInfo);
                     throw new DataStoreException(DataStoreUtils.ERROR_EXISTING_COMMANDSTREAM);
+                }
                 
                 // don't add if previous entry had a more recent valid time
                 // or if new entry is dated in the future
diff --git a/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryDataStreamStore.java b/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryDataStreamStore.java
index ef6764f61..50a70dbad 100644
--- a/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryDataStreamStore.java
+++ b/sensorhub-core/src/main/java/org/sensorhub/impl/datastore/mem/InMemoryDataStreamStore.java
@@ -224,8 +224,13 @@ protected synchronized IDataStreamInfo put(DataStreamKey dsKey, IDataStreamInfo
                 var newValidTime = dsInfo.getValidTime().begin();
                 
                 // error if datastream with same system/name/validTime already exists
+                // unless updating the same key
                 if (prevValidTime.equals(newValidTime))
+                {
+                    if (replace && key.equals(dsKey))
+                        return map.put(dsKey, dsInfo);
                     throw new DataStoreException(DataStoreUtils.ERROR_EXISTING_DATASTREAM);
+                }
                 
                 // don't add if previous entry had a more recent valid time
                 // or if new entry is dated in the future