Repair Tech for several years.
Computer hobyist repair and sales for many years.
Owner of several types of DVRs for the last few years and learning about them.
I have recently got my extra Replay TV 55xx unit with defective phone and ethernet to be activated and clock set.
A device could be made to set the clock with no encription needed just data entered directly as clock chip needs it.
Also the clock circuit is very poor with just a capacitor backup and no battery.
Some units have bad backup capacitors and would function much better with a battery in the system.
A bad backup capacitor can loose the time in just a short power outage or unplug etc.
A battery can run the clock for up to a number of years with only some normal drifting of time acuracy.
Thank You, Cy