diff --git a/Images/px4fmu-v4.prototype b/Images/px4fmu-v4.prototype
index 24e72f868d..949b4c54c0 100644
--- a/Images/px4fmu-v4.prototype
+++ b/Images/px4fmu-v4.prototype
@@ -7,6 +7,7 @@
     "summary": "PX4FMUv4",
     "version": "0.1",
     "image_size": 0,
+    "image_maxsize": 2080768,
     "git_identity": "",
     "board_revision": 0
 }