diff --git a/ROMFS/px4fmu_common/init.d/airframes/CMakeLists.txt b/ROMFS/px4fmu_common/init.d/airframes/CMakeLists.txt
index 80bd3b6e3b..b87a0b23e0 100644
--- a/ROMFS/px4fmu_common/init.d/airframes/CMakeLists.txt
+++ b/ROMFS/px4fmu_common/init.d/airframes/CMakeLists.txt
@@ -157,6 +157,8 @@ px4_add_romfs_files(
 	# [18000, 18999] High-altitude balloons
 	18001_TF-B1
 
+	# [22000, 22999] Reserve for custom models
+
 	24001_dodeca_cox
 
 	50000_generic_ground_vehicle