I don’t know how it was lock although some posters have said if you do not take the power off the receiver it will not happen for some time.so maybe unhook phone, sat and broadband but do not power it down
The theory is it needs to see the satellite when it boots I would say try at your own risk but do not be surprised if you cannot access the shows.
For me it was no big deal everything I need to see was on directv on demand and I was so happy with the genie that I did not care about the shows that I lost.
Ok this may not apply to the receiver the OP has. I have a 512 that was replaced by a 612. I had the 512 unplugged and sitting on the floor. A couple of weeks later I plugged it back in and hooked it up to my DVD recorder so I could get my 100 hours plus of old TCM movies off of it. I turned on the 512 and yes it says it cannot find a signal. I hit the guide button and then the DVR button. My recordings came up and I offloaded them to DVD.