@neebhaskaran: Dont fall for the customer service trick of motherboard. Kindly try the same with Airtel. If you face same issue with Airtel then its a hardware issue. I have also got the software upgraded. It works fine till the time market is not activated.
I tried another thing today. I have called vodafone customer care and disable Vodafone Live service. Account Sync is enable and no call drop since morning. I will try the same for 1-2 days and if there is call drop, there is another service from Vodafone i.e. GPRS data bearer service. If it doesnt have any impact of VMC, i will disable that service too and test.