diff --git a/source/drivers/MicroBitStorage.cpp b/source/drivers/MicroBitStorage.cpp
index 8fc5731..9994167 100644
--- a/source/drivers/MicroBitStorage.cpp
+++ b/source/drivers/MicroBitStorage.cpp
@@ -12,6 +12,8 @@
  */
 MicroBitStorage::MicroBitStorage()
 {
+    //initialise our magic block, if required.
+    size();
 }
 
 /*