Zebra GX420d retailer Shipping Label Thermal Printer

Product Name: Zebra GX420d retailer Shipping Label Thermal Printer
For sale is a GK420d Label Printer. I bought it here on eBay in excellent used condition. I used it regularly for shipping label printing until several years back. It hasn't had much use since then. It comes with the Original retailer usb b cable AC power brick A brand new three prong plug 2 boxes of labels (500 in a roll) The printer powers on and it was working when I last used it awhile ago. But the red and green lights are flashing, indicating that the firmware needs to be flashed. To do that, the manual stated it should be returned for service. Since I haven't used it regularly, it looks like it lost its settings. Otherwise the printer is in good physical condition. I've managed to get it to feed labels using the feed button. Windows does recognize it and the drivers installed. The printer just doesn't communicate with the computer. I don't know enough about the technical side of the printer to service it as is.