diff --git a/make/projects-dir.mk b/make/projects-dir.mk
index 58e8c1c0..9a1418de 100644
--- a/make/projects-dir.mk
+++ b/make/projects-dir.mk
@@ -98,7 +98,8 @@ ifneq ($(EXCLUDE_FROM_BUILD),)
 endif
 
 # non-interactive mode
-ifeq ($(shell echo $$PS1),)
+INTERACTIVE                 ?= n
+ifneq ($(INTERACTIVE),y)
   DASH_Y                    := -y
 endif