We upgraded two 6921 phones to the latest firmware, SCCP69xx.9-4-1-3SR1. What we are noticing is, the time is incorrect and it will not downgrade to any other version. It is currently registered to one of the CUCM, when I attempt to force it to register to another CUCM, through CUCM group. It won't.
We tried doing a factory reset, moved it to a different location. Still no luck.
If anyone has any troubleshooting steps or have encountered this issue before please let me know.