diff --git a/arch/arm/boards/phytec-som-imx6/lowlevel.c b/arch/arm/boards/phytec-som-imx6/lowlevel.c
index f9d70c7..05f918f 100644
--- a/arch/arm/boards/phytec-som-imx6/lowlevel.c
+++ b/arch/arm/boards/phytec-som-imx6/lowlevel.c
@@ -38,6 +38,7 @@
 	putc_ll('>');
 }
 
+#undef SZ_4G
 #define SZ_4G 0xEFFFFFF8
 
 BAREBOX_IMD_TAG_STRING(physom_mx6_memsize_SZ_128M, IMD_TYPE_PARAMETER, "memsize=128", 0);
diff --git a/include/linux/sizes.h b/include/linux/sizes.h
index ce3e815..fbde0bc 100644
--- a/include/linux/sizes.h
+++ b/include/linux/sizes.h
@@ -8,6 +8,8 @@
 #ifndef __LINUX_SIZES_H__
 #define __LINUX_SIZES_H__
 
+#include <linux/const.h>
+
 #define SZ_1				0x00000001
 #define SZ_2				0x00000002
 #define SZ_4				0x00000004
@@ -44,4 +46,6 @@
 #define SZ_1G				0x40000000
 #define SZ_2G				0x80000000
 
+#define SZ_4G				_AC(0x100000000, ULL)
+
 #endif /* __LINUX_SIZES_H__ */