diff --git a/Images/px4fmu-v5.prototype b/Images/px4fmu-v5.prototype
index 72ea08e328..8fecd6b86a 100644
--- a/Images/px4fmu-v5.prototype
+++ b/Images/px4fmu-v5.prototype
@@ -7,6 +7,7 @@
     "summary": "PX4FMUv5",
     "version": "0.1",
     "image_size": 0,
+    "image_maxsize": 2064384,
     "git_identity": "",
     "board_revision": 0
 }