diff --git a/arch/arm/lib/debug.S b/arch/arm/lib/debug.S
index ddee7c09c8..760ba74a3c 100644
--- a/arch/arm/lib/debug.S
+++ b/arch/arm/lib/debug.S
@@ -33,7 +33,7 @@
 
 #else /* !CONFIG_MMU */
 		.macro	addruart_current, rx, tmp1, tmp2
-		addruart	\rx, \tmp1
+		addruart	\rx, \tmp1, \tmp2
 		.endm
 
 #endif /* CONFIG_MMU */