diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
index ede77e0f1c41..309e7e335ab7 100644
--- a/arch/arm/boot/dts/stm32f429.dtsi
+++ b/arch/arm/boot/dts/stm32f429.dtsi
@@ -302,7 +302,7 @@ rtc: rtc@40002800 {
 			interrupt-parent = <&exti>;
 			interrupts = <17 1>;
 			interrupt-names = "alarm";
-			st,syscfg = <&pwrcfg>;
+			st,syscfg = <&pwrcfg 0x00 0x100>;
 			status = "disabled";
 		};