diff --git a/boards/arm/mps2_an521/mps2_an521.dts b/boards/arm/mps2_an521/mps2_an521.dts
index d69228b235a..2bb956645ca 100644
--- a/boards/arm/mps2_an521/mps2_an521.dts
+++ b/boards/arm/mps2_an521/mps2_an521.dts
@@ -79,7 +79,6 @@
 			mpu: mpu@e000ed90 {
 				compatible = "arm,armv8m-mpu";
 				reg = <0xe000ed90 0x40>;
-				arm,num-mpu-regions = <16>;
 			};
 		};
 	};