No, 'mobile data' was switched on. But: 'data roaming' was switched off after upgrade to OTA-12. I use the german provider 'Netzclub' (o2 / E-Plus), which allows data roaming within germany without extra charge. I activated 'data roaming' again, but the mobile data connection still wont work. Only reboot helped.
@Anupam:
No, 'mobile data' was switched on. But: 'data roaming' was switched off after upgrade to OTA-12. I use the german provider 'Netzclub' (o2 / E-Plus), which allows data roaming within germany without extra charge. I activated 'data roaming' again, but the mobile data connection still wont work. Only reboot helped.