I am doing project with chinese Arduino pro micro board which should be fully compatible with Arduino leonardo. I also upload standard "catherina-leonardo" bootloader into this module. Everythinks was working fine until I enable watchdog by "wdt_enable()" function in my code. Now It is not possible to upload new sketches via USB CDC serial port. I looks like processor do not wait in bootloader after software reset and jump to main program immediatly. Only way that restore processor from this state is erasing whole chip and upload new bootloader by external ISP programer. I think this is problem in bootloader. I need to use watchdog. Is there any fix or alternative bootloader for arduino leonardo?