diff --git a/arch/arm/boot/dts/sam9x60.dtsi b/arch/arm/boot/dts/sam9x60.dtsi
index ee6cc4329ae4..1e401a919f56 100644
--- a/arch/arm/boot/dts/sam9x60.dtsi
+++ b/arch/arm/boot/dts/sam9x60.dtsi
@@ -209,6 +209,7 @@
 					clock-names = "usart";
 					atmel,use-dma-rx;
 					atmel,use-dma-tx;
+					atmel,fifo-size = <16>;
 					status = "disabled";
 				};
 			};