diff --git a/op-build-env b/op-build-env
index 9cd5cb5..e6ca40e 100755
--- a/op-build-env
+++ b/op-build-env
@@ -5,6 +5,12 @@
     source ./customrc
 fi
 
+if [ ! -e buildroot/Makefile ]; then
+	echo "Please make sure you've checked out the buildroot submodule"
+	echo "  git submodule init && git submodule update"
+	return -1
+fi
+
 export BR2_EXTERNAL=${__PWD}/openpower
 export BR2_DL_DIR=${__PWD}/dl