1 files changed, 7 insertions, 0 deletions
diff --git a/lib/utils/printf.c b/lib/utils/printf.c
index 082b1c65a8..6dce896941 100644
--- a/lib/utils/printf.c
+++ b/lib/utils/printf.c
@@ -51,7 +51,14 @@ int vprintf(const char *fmt, va_list ap) {
 int DEBUG_printf(const char *fmt, ...) {
     va_list ap;
     va_start(ap, fmt);
+    #if MICROPY_DEBUG_STDERR
+    // Printing debug to stderr may give a chance tests which
+    // check stdout to pass, etc.
+    extern const mp_print_t mp_stderr_print;
+    int ret = mp_vprintf(&mp_stderr_print, fmt, ap);
+    #else
     int ret = mp_vprintf(&mp_plat_print, fmt, ap);
+    #endif
     va_end(ap);
     return ret;
 }