diff --git a/libs/blocksprj/main.blocks b/libs/blocksprj/main.blocks
index 5773d9b9..cf17f1bb 100644
--- a/libs/blocksprj/main.blocks
+++ b/libs/blocksprj/main.blocks
@@ -1,3 +1,3 @@
 <xml xmlns="http://www.w3.org/1999/xhtml">
-  <block type="pxtStart"></block>
+  <block type="pxt-on-start"></block>
 </xml>
\ No newline at end of file
diff --git a/libs/bluetoothprj/main.blocks b/libs/bluetoothprj/main.blocks
index 5773d9b9..cf17f1bb 100644
--- a/libs/bluetoothprj/main.blocks
+++ b/libs/bluetoothprj/main.blocks
@@ -1,3 +1,3 @@
 <xml xmlns="http://www.w3.org/1999/xhtml">
-  <block type="pxtStart"></block>
+  <block type="pxt-on-start"></block>
 </xml>
\ No newline at end of file