We think it's an old and expired security certificate.

That doesn't seem to make much sense ....

If it was an expired certificate on the Cable Card, it wouldn't work in any Tivo, but these cards do work in Series 4 and newer models

If it was an expired certificate on the Tivo, NO cable card would work, but Arris cards will work in a Tivo with this issue (I have a Tivo HD myself where the Motorola card started showing this error and I swapped it out for an Arris card and it works fine now)

Can you give any more detail on what lead you to the expired security certificate hypothesis?

Any response?

We think it's some combination potentially - certain cards need certain information from the TiVo. Other cards just don't work that way.

Well if you look in the Cable Labs spec, that error message is specifically spelled out.

"When the M-UDCP / Card pairing information screen application info APDU is selected after the Card has provided an invalid certificate to the M-UDCP then the M-UDCP SHALL generate and display the following message: "Please call your cable operator and report an invalid CableCARD"

So the error is when the card provides an invalid cert. But we know the cert can't be bad on the card because if it was, it would be bad in all Tivo's, since the Cable Labs spec is identical across models. So the Series 3 is trying to get the cert off the Motorola cable card but not getting it, but it does get it off an Arris card. Do we know the different ways a Tivo can access a Cable Card cert?

Anyone? Or is Weakness not looking into this issue further?

We are not.