diff --git a/fdts/stm32mp151a-prtt1a-fw-config.dts b/fdts/stm32mp151a-prtt1a-fw-config.dts
new file mode 100644
index 0000000..1bbae4e
--- /dev/null
+++ b/fdts/stm32mp151a-prtt1a-fw-config.dts
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright (c) 2023, Oleksij Rempel <kernel@pengutronix.de>, Pengutronix
+ */
+
+#define DDR_SIZE	0x10000000 /* 256 MB */
+#include "stm32mp15-fw-config.dtsi"