diff --git a/libsel4platsupport/src/common.c b/libsel4platsupport/src/common.c
index a1f130e5..a8fa0238 100644
--- a/libsel4platsupport/src/common.c
+++ b/libsel4platsupport/src/common.c
@@ -268,8 +268,8 @@ static void __serial_setup()
     case NOT_INITIALIZED:
 #ifdef CONFIG_LIB_SEL4_PLAT_SUPPORT_USE_SEL4_DEBUG_PUTCHAR
         setup_status = SETUP_COMPLETE;
-        printf("\nWarning: using printf before serial is set up. This only works as your\n");
-        printf("printf is backed by seL4_Debug_PutChar()\n");
+        seL4_DebugPutString("\nWarning: using printf before serial is set up. This only works as your\n"
+                            "printf is backed by seL4_Debug_PutChar()\n");
         started_regular = 1;
 #else
         /* attempt failsafe initialization and print something out */