E:footer is wrong during installation of stock rom on lenovo a6000 plus

I had rooted lenovo A6000 plus using kingroot. Then i updated the phone (system update). though they gave the warning as your phone is rooted the update might not work but still i updated :( . when the phone restarted there are options for recovery (Android system recovery<3e> kraft-A6000-s_S013_150615). when i update the custom rom (even stock rom) there are two errors 1.E:footer is wrong and
2. E:signature verification failed. then installation got aborted. i have gone through factory reset also tried to install from sd card still no luck.
now how can i install rom or recover. i have no backups though :(.