OTA works on this phone but be sure to change the SPC to 000000, otherwise phone will not accept OTA with wrong SPC, the steps are simple for this phone. As the phone is virgin branded, you need to first get the SPC to even enable the diag port for programming parameters. To get this, unlock bootloader via htcdev.com, root the phone with unsecured boot.img available over xda, install MSL finder from play store. Once you got the MSL/SPC, you can enable to DIAG Port.
I dont think its possible yet with TATA to get meid registered, they are allowing foreign meid's previously but then stopped due to illegal cloning activities. However meid/esn registering with TATA is also known, evdo will not work on those meid/esn due to lack of knowledge of tata guys. Only 1x work with registered tata meid's.
Arjun, yes i have flashed many of them.