Yes, this was i did when i encountered this error. from PR1.2 i downgraded into PR1.1, then I've encountered NO SIM CARD status. I didn't worried, maybe PR1.2 has ability to disable this, and then i go back to PR1.2 in which i believed that the latest firmware will resolve this issue.

Apparently, still the GENERAL ERROR in call function is not working. currently i don't have any option how to resolve this.

If you could help me on this, i would highly appreciate it.