diff --git a/hw/arm/mps2-tz.c b/hw/arm/mps2-tz.c
index 6b24aaacde..f8b620bcc6 100644
--- a/hw/arm/mps2-tz.c
+++ b/hw/arm/mps2-tz.c
@@ -38,6 +38,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/units.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "hw/arm/boot.h"
@@ -458,7 +459,7 @@ static void mps2tz_common_init(MachineState *machine)
      * call the 16MB our "system memory", as it's the largest lump.
      */
     memory_region_allocate_system_memory(&mms->psram,
-                                         NULL, "mps.ram", 0x01000000);
+                                         NULL, "mps.ram", 16 * MiB);
     memory_region_add_subregion(system_memory, 0x80000000, &mms->psram);
 
     /* The overflow IRQs for all UARTs are ORed together.
diff --git a/hw/arm/mps2.c b/hw/arm/mps2.c
index 10efff36b2..d002b126d3 100644
--- a/hw/arm/mps2.c
+++ b/hw/arm/mps2.c
@@ -23,6 +23,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/units.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "hw/arm/boot.h"
@@ -146,7 +147,7 @@ static void mps2_common_init(MachineState *machine)
      * zbt_boot_ctrl is always zero).
      */
     memory_region_allocate_system_memory(&mms->psram,
-                                         NULL, "mps.ram", 0x1000000);
+                                         NULL, "mps.ram", 16 * MiB);
     memory_region_add_subregion(system_memory, 0x21000000, &mms->psram);
 
     switch (mmc->fpga_type) {