Lenovo a850 problem with SIM card undetected because missing of Imei and baseband info lead to comm failure.
Even though SIM card is inserted, but notification remains with SIM card not inserted
Cause of the problem
User said it suddenly happened after he changed SIM card
Corrupted nvram may cause from system update or suddenly remove simcard so that as a precaution turn off handphone before removing the SIM card to ensure system data were not affected or corrupted and if any ongoing