2 files changed, 3 insertions, 1 deletions
diff --git a/shared/tinyusb/mp_usbd.h b/shared/tinyusb/mp_usbd.h
index ef3234845..31234566b 100644
--- a/shared/tinyusb/mp_usbd.h
+++ b/shared/tinyusb/mp_usbd.h
@@ -125,7 +125,6 @@ inline static bool mp_usb_device_builtin_enabled(const mp_obj_usb_device_t *usbd
 
 static inline void mp_usbd_init(void) {
     // Without runtime USB support, this can be a thin wrapper wrapper around tusb_init()
-    extern bool tusb_init(void);
     tusb_init();
 }
 
diff --git a/shared/tinyusb/mp_usbd_cdc.c b/shared/tinyusb/mp_usbd_cdc.c
index 63d015cb4..c6a88e467 100644
--- a/shared/tinyusb/mp_usbd_cdc.c
+++ b/shared/tinyusb/mp_usbd_cdc.c
@@ -95,6 +95,9 @@ void tud_cdc_rx_cb(uint8_t itf) {
 }
 
 mp_uint_t mp_usbd_cdc_tx_strn(const char *str, mp_uint_t len) {
+    if (!tusb_inited()) {
+        return 0;
+    }
     size_t i = 0;
     while (i < len) {
         uint32_t n = len - i;