diff --git a/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/BaseInstanceEnabler.java b/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/BaseInstanceEnabler.java
index ba382b96b8..5d729170b1 100644
--- a/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/BaseInstanceEnabler.java
+++ b/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/BaseInstanceEnabler.java
@@ -184,7 +184,7 @@ public WriteResponse write(ServerIdentity identity, int resourceid, int resource
                 if (instances.containsKey(resourceInstanceId)) {
                     instances.put(resourceInstanceId, value);
                     return write(identity, resourceid,
-                            new LwM2mMultipleResource(resourceInstanceId, value.getType(), instances.values()));
+                        new LwM2mMultipleResource(resourceid, value.getType(), instances.values()));
                 }
             }
         }
diff --git a/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/DummyInstanceEnabler.java b/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/DummyInstanceEnabler.java
index 587203bc8d..ff528bf27e 100644
--- a/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/DummyInstanceEnabler.java
+++ b/leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/DummyInstanceEnabler.java
@@ -96,6 +96,7 @@ protected LwM2mMultipleResource initializeMultipleResource(ObjectModel objectMod
         switch (resourceModel.type) {
         case STRING:
             values.put(0, createDefaultStringValueFor(objectModel, resourceModel));
+            values.put(1, createDefaultStringValueFor(objectModel, resourceModel));
             break;
         case BOOLEAN:
             values.put(0, createDefaultBooleanValueFor(objectModel, resourceModel));
diff --git a/leshan-core/src/main/java/org/eclipse/leshan/core/node/codec/text/LwM2mNodeTextEncoder.java b/leshan-core/src/main/java/org/eclipse/leshan/core/node/codec/text/LwM2mNodeTextEncoder.java
index 1d3d2fd268..44e847abd7 100644
--- a/leshan-core/src/main/java/org/eclipse/leshan/core/node/codec/text/LwM2mNodeTextEncoder.java
+++ b/leshan-core/src/main/java/org/eclipse/leshan/core/node/codec/text/LwM2mNodeTextEncoder.java
@@ -100,7 +100,7 @@ public void visit(LwM2mResource resource) {
         public void visit(LwM2mResourceInstance instance) {
             LOG.trace("Encoding resource instance {} into text", instance);
 
-            ResourceModel rSpec = model.getResourceModel(path.getObjectId(), instance.getId());
+            ResourceModel rSpec = model.getResourceModel(path.getObjectId(), path.getResourceId());
             Type expectedType = rSpec != null ? rSpec.type : instance.getType();
             Object val = converter.convertValue(instance.getValue(), instance.getType(), expectedType, path);
 
diff --git a/leshan-integration-tests/src/test/java/org/eclipse/leshan/integration/tests/WriteTest.java b/leshan-integration-tests/src/test/java/org/eclipse/leshan/integration/tests/WriteTest.java
index 63b8bea6f1..2146274b4c 100644
--- a/leshan-integration-tests/src/test/java/org/eclipse/leshan/integration/tests/WriteTest.java
+++ b/leshan-integration-tests/src/test/java/org/eclipse/leshan/integration/tests/WriteTest.java
@@ -202,34 +202,40 @@ private void write_integer_resource(ContentFormat format) throws InterruptedExce
 
     @Test
     public void can_write_string_resource_json_instance() throws InterruptedException {
-        write_string_resource_instance(ContentFormat.JSON);
+        write_string_resource_instance(ContentFormat.JSON, 0);
     }
 
     @Test
     public void can_write_string_resource_old_json_instance() throws InterruptedException {
-        write_string_resource_instance(ContentFormat.fromCode(ContentFormat.OLD_JSON_CODE));
+        write_string_resource_instance(ContentFormat.fromCode(ContentFormat.OLD_JSON_CODE), 0);
     }
 
     @Test
     public void can_write_string_resource_text_instance() throws InterruptedException {
-        write_string_resource_instance(ContentFormat.TEXT);
+        write_string_resource_instance(ContentFormat.TEXT, 0);
+    }
+
+    @Test
+    public void can_write_string_multiple_resource_text_instance() throws InterruptedException {
+        write_string_resource_instance(ContentFormat.TEXT, 0);
+        write_string_resource_instance(ContentFormat.TEXT, 1);
     }
 
     @Test
     public void can_write_string_resource_tlv_instance() throws InterruptedException {
-        write_string_resource_instance(ContentFormat.TLV);
+        write_string_resource_instance(ContentFormat.TLV, 0);
     }
 
     @Test
     public void can_write_string_resource_old_tlv_instance() throws InterruptedException {
-        write_string_resource_instance(ContentFormat.fromCode(ContentFormat.OLD_TLV_CODE));
+        write_string_resource_instance(ContentFormat.fromCode(ContentFormat.OLD_TLV_CODE), 0);
     }
 
-    private void write_string_resource_instance(ContentFormat format) throws InterruptedException {
+    private void write_string_resource_instance(ContentFormat format, int resourceInstance) throws InterruptedException {
         // read device model number
         String valueToWrite = "newValue";
         WriteResponse response = helper.server.send(helper.getCurrentRegistration(),
-                new WriteRequest(format, TEST_OBJECT_ID, 0, STRING_RESOURCE_INSTANCE_ID, 0, valueToWrite, Type.STRING));
+            new WriteRequest(format, TEST_OBJECT_ID, 0, STRING_RESOURCE_INSTANCE_ID, resourceInstance, valueToWrite, Type.STRING));
 
         // verify result
         assertEquals(CHANGED, response.getCode());
@@ -238,7 +244,7 @@ private void write_string_resource_instance(ContentFormat format) throws Interru
 
         // read resource to check the value changed
         ReadResponse readResponse = helper.server.send(helper.getCurrentRegistration(),
-                new ReadRequest(format, TEST_OBJECT_ID, 0, STRING_RESOURCE_INSTANCE_ID, 0));
+            new ReadRequest(format, TEST_OBJECT_ID, 0, STRING_RESOURCE_INSTANCE_ID, resourceInstance));
 
         // verify result
         LwM2mResourceInstance resource = (LwM2mResourceInstance) readResponse.getContent();