diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index d83c862182..5ea5417917 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -644,7 +644,7 @@ int os_get_filesize(const char *fname, long long *size)
 
 void os_putc(int ch)
 {
-	fputc(ch, stdout);
+	os_write(1, &ch, 1);
 }
 
 void os_puts(const char *str)