diff --git a/src/NimBLEAttValue.cpp b/src/NimBLEAttValue.cpp
index 8dbe4866..be769595 100644
--- a/src/NimBLEAttValue.cpp
+++ b/src/NimBLEAttValue.cpp
@@ -124,9 +124,9 @@ NimBLEAttValue& NimBLEAttValue::append(const uint8_t* value, uint16_t len) {
 
     uint8_t* res     = m_attr_value;
     uint16_t new_len = m_attr_len + len;
-    if (new_len > m_capacity) {
-        res        = static_cast<uint8_t*>(realloc(m_attr_value, (new_len + 1)));
-        m_capacity = new_len;
+    bool     grow    = new_len > m_capacity;
+    if (grow) {
+        res = static_cast<uint8_t*>(realloc(m_attr_value, (new_len + 1)));
     }
     NIMBLE_CPP_DEBUG_ASSERT(res);
     if (res == nullptr) {
@@ -134,6 +134,10 @@ NimBLEAttValue& NimBLEAttValue::append(const uint8_t* value, uint16_t len) {
         return *this;
     }
 
+    if (grow) {
+        m_capacity = new_len;
+    }
+
 # if MYNEWT_VAL(NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED)
     time_t t = time(nullptr);
 # else