I have a Motorola MZ602; it won't recognize the SIM card. I have done the factory reset, then installed the SIM; I've actually tried TWO different SIM cards - each is a different format from the other - and after the reset the error message is that the "SIM card not found".
I've gone to three different Verizon corporate stores and the only thing they have done is provided me with the SIMs
More about :motorola xoom mz602 recognize sim card
You have two options here, either the SIM card is the wrong type to use with that device, or the device is bad. Since you tried a couple of SIM cards, need to have the Xoom repaired or replaced.