Thanks. How are you flashing the firmware? I tried using Atmel Flip like on a KMAC but I get "atlibdfuusb.dll not found" and "could not load dynamic library" when I try to find the Viper using "USB" option.
you probably haven't update the driver for the viper i think.
open device manager > find the particular usb device with "!" > browse atmel folder driver to install it.
something similar like flashing kmac firmware as well if u are using flip method.
the other method is using dfu_programmer folder & files provided by 02D if u doesn't have atmel flip installed on your pc.
same holding capslock when connecting the viper, then install driver (skip this part if u already done it before), use the 02D keymapper upload firmware and select the .hex file u mapped.
black window will pop out stating the firmware is uploading to your viper and wait a few sec press any key to proceed, done.