diff --git a/ports/opencv/CONTROL b/ports/opencv/CONTROL
index 0c9766079a..47fe19d0c0 100644
--- a/ports/opencv/CONTROL
+++ b/ports/opencv/CONTROL
@@ -1,4 +1,6 @@
 Source: opencv
 Version: 3.2.0
 Build-Depends: zlib, libpng, libjpeg-turbo, tiff
+#Use the following line instead for optional features from OpenCV-contrib that require protobuf
+#Build-Depends: zlib, libpng, libjpeg-turbo, tiff, protobuf
 Description: computer vision library