Update keymind retry controls

src/helpers/ArduinoSerialInterface.cpp

@@ -17,6 +17,10 @@ bool ArduinoSerialInterface::isConnected() const {
   return true;   // no way of knowing, so assume yes
 }
 
+bool ArduinoSerialInterface::isReadBusy() const {
+  return false;
+}
+
 bool ArduinoSerialInterface::isWriteBusy() const {
   return false;
 }