diff --git a/Makefile b/Makefile
index 5e7c1be..c183b3d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,10 @@
 #
 # KBUILD build parameters.
 #
-KERNEL_SOURCES  ?= /lib/modules/$(shell uname -r)/build
+MODULE_DIR = /lib/modules/$(shell uname -r)
+KERNEL_SOURCES  ?= $(MODULE_DIR)/build
 KERNEL_HEADERS  := -I$(KERNEL_SOURCES)/include
-MODULE_ROOT     ?= /lib/modules/$(shell uname -r)/CiscoVPN
+MODULE_ROOT     ?= $(MODULE_DIR)/CiscoVPN
 SUBARCH         := $(shell uname -m)
 
 
@@ -12,7 +13,9 @@ MODULE_NAME := cisco_ipsec
 SOURCE_OBJS := linuxcniapi.o frag.o IPSecDrvOS_linux.o interceptor.o linuxkernelapi.o
 
 ifeq ($(SUBARCH),x86_64)
-CFLAGS += -mcmodel=kernel -mno-red-zone
+# Must NOT fiddle with CFLAGS
+# CFLAGS += -mcmodel=kernel -mno-red-zone
+EXTRA_CFLAGS += -mcmodel=kernel -mno-red-zone
 NO_SOURCE_OBJS := libdriver64.so
 else
 NO_SOURCE_OBJS := libdriver.so