diff --git a/Makefile b/Makefile
index 323d646..1001bc5 100644
--- a/Makefile
+++ b/Makefile
@@ -624,8 +624,9 @@
 UBOOTINCLUDE    := \
 		-Iinclude \
 		$(if $(KBUILD_SRC), -I$(srctree)/include) \
-		$(if $(CONFIG_SYS_THUMB_BUILD), $(if $(CONFIG_HAS_THUMB2),, \
-			-I$(srctree)/arch/$(ARCH)/thumb1/include),) \
+		$(if $(CONFIG_$(SPL_)SYS_THUMB_BUILD), \
+			$(if $(CONFIG_HAS_THUMB2),, \
+				-I$(srctree)/arch/$(ARCH)/thumb1/include),) \
 		-I$(srctree)/arch/$(ARCH)/include \
 		-include $(srctree)/include/linux/kconfig.h