diff --git a/Kbuild b/Kbuild
index 94de5cf..271696c 100644
--- a/Kbuild
+++ b/Kbuild
@@ -2145,6 +2145,9 @@
 #Set RX_PERFORMANCE
 cppflags-$(CONFIG_RX_PERFORMANCE) += -DRX_PERFORMANCE
 
+#Set QCS403_MEM_OPTIMIZE
+cppflags-$(CONFIG_QCS403_MEM_OPTIMIZE) += -DQCS403_MEM_OPTIMIZE
+
 #Enable OL debug and wmi unified functions
 cppflags-$(CONFIG_ATH_PERF_PWR_OFFLOAD) += -DATH_PERF_PWR_OFFLOAD