Is the implication that software cannot be hacked any easier than hardware-entered keys? I am failing to understand the meat of your post other than to criticize FTP. Please remember that I am only passing on what I know, and I am not responsible for the network infrastructure.
It is clear the hardware knows what the upgrade key is based on serial number. My guess is some sort of salted hash.
Since you generate the key from the Uniden site, the risk is the same regardless of the entry mode. I don’t understand why entering it via software would be any riskier than entering it through the scanner itself, considering the software isn’t generating the key.
I should also add that Uniden’s reliance on FTP is not solely within your network engineering group.