Arduino Nano /Uno USB is not getting recognized I have multiple Unos and Nano and recently due to some bad configuration the USBs are not getting recognised on my Mac Air Laptop. These were working models for almost 1-2 years. I used it to control motors and something must have happened and it stopped.

But strangely the small boot up LEDs on the Nano/Uno light up when connected so it seems that the connection from the laptop USB to the device is good - but the driver ports are not showing up on the Arduino IDE.
How do I go about resolving that it is not just a software issue and is a hardware issue ?

I reinstalled the CH340G driver.img and yet the device when plugged in - does not show the USB port on the IDE ?
Any thoughts or ideas on how to resolve this.

The Uno/Nano are Chinese Clones and have CH340 chipset on them.
Is there some firmware that may have gone wrong and can be reset ? or new boot loader that can be burnt to bring them back to life.

I want to be able to see the Tools-> Port -> /dev/cu.usbserial1410 
and also be able to see /dev/cu.usbserial on the command xterm prompt .
Assuming that the atmega328p still works fine, you can still use the Nano. I have solved this a few times by just using a FTDI breakout board (remember to set it to 5V, though 3V3 upload works on a Nano), and connecting RX to TX, TX to RX. Press reset before each upload.