bootloader: show red LED on BV

bootloader.c

@@ -81,6 +81,9 @@ void main(void)
 	rcc_clock_setup_in_hse_8mhz_out_72mhz(); // start main clock
 	board_setup(); // setup board to control LED
 	led_on(); // indicate bootloader started
+#if defined(BUSVOODOO)
+	led_toggle(); // switch to red LED
+#endif
 	usb_dfu_setup(); // setup USB DFU for firmware upload
 	usb_dfu_start(); // run DFU mode
 }