diff --git a/arch/arm/boot/dts/armada-xp-matrix.dts b/arch/arm/boot/dts/armada-xp-matrix.dts
index e47c49ecd55c..c2242745b9b8 100644
--- a/arch/arm/boot/dts/armada-xp-matrix.dts
+++ b/arch/arm/boot/dts/armada-xp-matrix.dts
@@ -23,7 +23,12 @@ chosen {
 
 	memory {
 		device_type = "memory";
-		reg = <0 0x00000000 0 0x80000000>; /* 2 GB */
+		/*
+		 * This board has 4 GB of RAM, but the last 256 MB of
+		 * RAM are not usable due to the overlap with the MBus
+		 * Window address range
+		 */
+		reg = <0 0x00000000 0 0xf0000000>;
 	};
 
 	soc {