D440 Companion Link failure

[Soniclife]

I just received my upgraded D440 Pro few days ago and tried last night.  I installed it and it was working as of last night.

But today when I turn it on, the companion would not link

I tried unplugging and reloading the config file with same result

The companion boots up, loads "S1 config", but would not do the ADH and SAM load

It gives me the status page with:  "Companion Mode:ON, INPUT:RS232;  "Link Status:NONE"

I tried everything, including:
- Changing the SPDIF cable between the Master and the Companion
- disabling the link cable
- Boot up both machines with no SD card and try again
- Unplugging and replugging in both units repeatedly
- Reformat and use a different SD card

I know the physical connection is correct, because it was working fine yesterday.

Please is there anything else I should try before declaring it dead?

The times this has happened to me during setup it has been one of the two cables not seated correctly, or firmware versions being different. Now I don't see how the firmware could change by itself, but a cable that wasn't 100% correct could come undone.