On software controllable serial power pins, keep power off during bootloader (#1882)

radio/src/targets/common/arm/stm32/bootloader/boot.cpp

@@ -219,6 +219,17 @@ int main()
   pwrInit();
   keysInit();
 
+#if defined(SWSERIALPOWER)
+  #if defined(AUX_SERIAL)
+    void set_aux_pwr(uint8_t on);
+    set_aux_pwr(0);
+  #endif
+  #if defined(AUX2_SERIAL)
+    void set_aux2_pwr(uint8_t on);
+    set_aux2_pwr(0);
+  #endif
+#endif
+
   // wait a bit for the inputs to stabilize...
   if (!WAS_RESET_BY_WATCHDOG_OR_SOFTWARE()) {
     for (uint32_t i = 0; i < 150000; i++) {