diff --git a/libraries/EEPROM/src/EEPROM.h b/libraries/EEPROM/src/EEPROM.h
index 315c4e0..780a89e 100644
--- a/libraries/EEPROM/src/EEPROM.h
+++ b/libraries/EEPROM/src/EEPROM.h
@@ -94,7 +94,7 @@ struct EEPROMClass{
     uint16_t length()                    { return (uint16_t)EEPROM_LENGHT; }
     
     template< typename T >
-    T &put(int idx, T &data)
+    const T &put(int idx, const T &data)
     {
         void* dataPointer = (void*)&data;
         // check if idx is valid