diff --git a/esp32/telelogger/telestore.cpp b/esp32/telelogger/telestore.cpp
index 4eeec8c..fe77199 100644
--- a/esp32/telelogger/telestore.cpp
+++ b/esp32/telelogger/telestore.cpp
@@ -107,7 +107,7 @@ void CStorageRAM::header(const char* devid)
 void CStorageRAM::tailer()
 {
     if (m_cache[m_cacheBytes - 1] == ',') m_cacheBytes--;
-    m_cacheBytes += sprintf(m_cache + m_cacheBytes, "*%X", (unsigned int)checksum(m_cache, m_cacheBytes));
+    m_cacheBytes += sprintf(m_cache + m_cacheBytes, "*%02X", (unsigned int)checksum(m_cache, m_cacheBytes));
 }
 
 void CStorageRAM::untailer()