Default [Q] Phone keeps saying "Preparing SIM card"

I installed the latest RUU from HTC (4.13.651.4) Phone is S-OFF.

Immediately, upon first boot, the phone keeps saying "Preparing SIM card..." There is nothing that seems to stop it. I have reflashed the firmware, ran the RUU several times, ##72786# reset, but the phone keeps going in this endless loop of "Preparing SIM card", which drains the battery and even turns off the cellular radio at random times.

Sprint support has no clue and I am basically left with no options at this point.

What can be done -- do I need a new phone??