diff --git a/shared-module/storage/__init__.c b/shared-module/storage/__init__.c
index db994158d6489..5c743377df74b 100644
--- a/shared-module/storage/__init__.c
+++ b/shared-module/storage/__init__.c
@@ -149,7 +149,7 @@ void common_hal_storage_remount(const char *mount_path, bool readonly, bool disa
         mp_raise_OSError(MP_EINVAL);
     }
 
-    #ifdef USB_AVAILABLE
+    #if CIRCUITPY_USB_MSC
     if (!usb_msc_ejected()) {
         mp_raise_RuntimeError(translate("Cannot remount '/' when USB is active."));
     }
diff --git a/supervisor/usb.h b/supervisor/usb.h
index 1c709926a7118..f8fd713715f1c 100644
--- a/supervisor/usb.h
+++ b/supervisor/usb.h
@@ -54,8 +54,10 @@ void usb_init(void);
 void usb_disconnect(void);
 
 // Propagate plug/unplug events to the MSC logic.
+#if CIRCUITPY_USB_MSC
 void usb_msc_mount(void);
 void usb_msc_umount(void);
 bool usb_msc_ejected(void);
+#endif
 
 #endif // MICROPY_INCLUDED_SUPERVISOR_USB_H