diff --git a/hal/mpu/mbed_mpu_v7m.c b/hal/mpu/mbed_mpu_v7m.c
index 5c48554a4a..63bdc32b1c 100644
--- a/hal/mpu/mbed_mpu_v7m.c
+++ b/hal/mpu/mbed_mpu_v7m.c
@@ -163,7 +163,7 @@ void mbed_mpu_init()
             0,                          // IsShareable
             1,                          // IsCacheable
             0,                          // IsBufferable
-            ~0U,                        // SubRegionDisable
+            0U,                         // SubRegionDisable
             ARM_MPU_REGION_SIZE_512MB)  // Size
     );