TFTP is so old-school, and even with WinSCP, you may have limited storage on your JunOS device to copy the somewhat sizable firmware ware file to. Or perhaps you just need a faster way to do it. In some cases, the GUI on earlier code versions is not very cooperative with software updates either. If any of these situations apply to you, I have good news. The USB on the back of most EX series switches, or available on other JunOS devices, is typically functional and we can use that port to install a firmware file from a USB flash drive with relative ease.