diff --git a/configure/CONFIG_APP b/configure/CONFIG_APP
index ea0f0553ecb799196afe13669e0069a658604fb3..ae3b4f2655ad42a9a209c8874b112933a106d373 100644
--- a/configure/CONFIG_APP
+++ b/configure/CONFIG_APP
@@ -23,4 +23,4 @@ HOST_OPT=NO
 
 E3_LIBRARY_NAME := require
 E3_LIBRARY_VERSION := 6.6.6
-EPICS_MODULES:=$(EPICS_BASE)/modules
\ No newline at end of file
+EPICS_MODULES?=$(EPICS_BASE)/modules
\ No newline at end of file