You should be able to do the firmware update again. Setup the firmware program by starting it and then load the proper BIN file into it. Connect the USB dongle to the computer and make sure the COM port is selected and accepted. Plug the USB dongle into the radio which should be off. Then press the PTT button and turn the radio on. The blue bar on the program should start moving up. I don't know if you can release the PTT button or not, I don't until the update is complete. When it does complete press the END button, turn off the radio, unplug the USB dongle and turn the radio back on.
Hopefully it works.